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Summer newborn essentials: what a baby born in the heat needs

In shortA baby born on July 15, 2027 wears sizes NB and 3M from July to September. In hot months the list moves to short sleeves: in Houston, size NB takes 4 short-sleeve bodysuits and 2 short-sleeve rompers, against 2 and 1 in Chicago, where those weeks count as mild. For sizes NB and 3M together, the hot-month list has 6 fewer pieces than the mild-month one, with balanced amounts.

Summer, on Cotokim's calendar for the US, is June, July, and August. For the clothes, a month counts as hot from 75 °F (24 °C) up, a Cotokim proposal, using the typical weather of each city from NOAA's climate normals 1. Not every US summer is hot by that cutoff, so the city decides: see Chicago, New York City, Houston, Miami or any of the 100 cities.

A July baby in four cities

A baby born on July 15, 2027, balanced amounts, laundry every two days, with a dryer:

Size NB:

CityShort-sleeve bodysuitsShort-sleeve rompersAll NB clothes
Chicago2112 pieces and 5 pairs
New York City4210 pieces and 4 pairs
Houston4210 pieces and 4 pairs
Miami4210 pieces and 4 pairs

Size 3M:

CityShort-sleeve bodysuitsShort-sleeve rompersAll 3M clothes
Chicago3217 pieces and 4 pairs
New York City4317 pieces and 4 pairs
Houston5413 pieces and 3 pairs
Miami5413 pieces and 3 pairs

This is the reason the list gives for the short-sleeve bodysuits in Houston:

4 short-sleeve bodysuits: your baby will wear size NB · newborn between July and August, with hot weather in Houston, and you do laundry every two days.

71 items on the list for the birth and the first 6 months, with 1,432 diapers, for the weather in New York City.

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The first 6 months in New York City

  1. Feb36°F2.2 °CcoldNB
  2. Mar43°F6.0 °CcoldNB and 3M
  3. Apr54°F12.1 °Ccold3M
  4. May63°F17.3 °Ccold3M and 6M
  5. Jun72°F22.2 °Cmild6M
  6. Jul78°F25.3 °Chot6M
  7. Aug76°F24.5 °Chot6M and 9M

The first and last months count only the days that fall within the first 6 months. Typical weather: NOAA U.S. Climate Normals (1991-2020), station NEW YORK CNTRL PK TWR, NY US, 5 mi (8 km) away.

Tap a phase to see the items, the amounts and the reason behind each number. The amounts are a Cotokim proposal.

Phase 1: Ready for the birth

44 items

Clothes

  • 2Short-sleeve bodysuitNBWhy?

    2 short-sleeve bodysuits: your baby will wear size NB · newborn between February and March, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Long-sleeve bodysuitNBWhy?

    2 long-sleeve bodysuits: your baby will wear size NB · newborn between February and March, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Sleeper or footie (long sleeves and legs)NBWhy?

    2 sleepers: your baby will wear size NB · newborn between February and March, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 1Short-sleeve romperNBWhy?

    1 short-sleeve romper: your baby will wear size NB · newborn between February and March, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Footed or pull-on pantsNBWhy?

    2 pairs of pants: your baby will wear size NB · newborn between February and March, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Cardigan or light jacketNBWhy?

    3 cardigans or light jackets: your baby will wear size NB · newborn between February and March, with cold weather in New York City.

  • 3SocksNBWhy?

    3 pairs of socks: your baby will wear size NB · newborn between February and March, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Scratch mittens (optional)NBWhy?

    2 pairs of scratch mittens: optional, for the first weeks. Short, filed nails are the alternative.

  • 2Knit hat (for going out in the cold)NBWhy?

    2 knit hats: for going out on cold days; your baby will wear size NB · newborn between February and March, with cold weather in New York City.

  • 1Snowsuit or bunting (for going out in freezing weather)3MWhy?

    1 snowsuit or bunting: for going out on freezing days; your baby will wear size 3M · 0 to 3 months between February and May in New York City. Take it off before buckling the car seat and when you get home.

Sleep

  • 1CribWhy?

    1 crib: a sleep space just for your baby, with a firm mattress and only a fitted sheet inside.

  • 1Crib mattressWhy?

    1 crib mattress: firm and flat, covered only by a fitted sheet.

  • 3Fitted crib sheetWhy?

    3 fitted crib sheets: one on the mattress, one in the wash and spares for nights when the diaper leaks; you do laundry every two days.

  • 2Waterproof mattress coverWhy?

    2 waterproof mattress covers: one on the mattress and one in the wash.

  • 2Wearable blanket (sleep sack)Why?

    2 wearable blankets: keeps your baby warm without a blanket in the crib; with cold (February, March, April, and May), mild (June), and hot (July and August) weather in New York City in the first months, choose the TOG by your room temperature. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Swaddle (blanket or wearable)Why?

    3 swaddles: for the first weeks, until your baby tries to roll; you do laundry every two days.

  • 3Baby blanket (for holding and outings)Why?

    3 baby blankets: for holding and outings, with cold (February, March, April, and May), mild (June), and hot (July and August) weather in New York City in the first months.

Bath and hygiene

  • 1Baby bathtubWhy?

    1 baby bathtub: one per home is enough, even with twins (one bath at a time).

  • 2Hooded towelWhy?

    2 hooded towels: one in use, one in the wash and one spare; you do laundry every two days.

  • 1Mild baby washWhy?

    1 bottle of baby wash: a bottle lasts weeks at first; buy more when you open the last one.

  • 1Baby nail file and clippers (or rounded scissors)Why?

    1 nail care kit: one per home is enough.

  • 1Cotton balls or pads (optional)Why?

    1 pack of cotton balls: optional; buy more as you go.

Diapering

  • 348Disposable diapersNWhy?

    348 size N diapers (about 3 packs): your baby will likely wear this size for about 5 weeks, with 8 to 12 changes a day.

  • 3Fragrance-free baby wipesWhy?

    3 packs of wipes: for the first weeks; Pampers says newborns may need about 20 to 30 wipes a day, so buy more as you go.

  • 1Diaper rash barrier creamWhy?

    1 tube of diaper cream: a tube lasts weeks at first; buy more when it runs low.

  • 1Portable changing padWhy?

    1 portable changing pad: it stays in the diaper bag.

  • 1Changing pad (for a dresser)Why?

    1 changing pad: saves your back at changing time.

Out and about

  • 1Infant car seat (rear-facing)Why?

    1 infant car seat: your baby should ride rear-facing from the first ride home from the hospital.

  • 1Diaper bagWhy?

    1 diaper bag: goes on every outing; it can be the hospital bag too.

  • 1Mosquito net for stroller and carrier (optional)Why?

    1 mosquito net: optional, for mosquito season in the first months, with cold (February, March, April, and May), mild (June), and hot (July and August) weather in New York City.

Feeding

  • 7Burp clothWhy?

    7 burp cloths: three or four a day go in the wash; you do laundry every two days.

  • 1Nursing pillow (optional)Why?

    1 nursing pillow: optional, for mom's comfort; it stays out of the crib.

Nursery

  • 1Room thermometerWhy?

    1 room thermometer: sleepwear and the sleep sack's TOG are chosen by the room temperature.

  • 1Dim night lightWhy?

    1 night light: for night feeds, without turning on the bright light.

  • 1Laundry hamperWhy?

    1 laundry hamper: helps you keep your laundry routine.

Health

  • 1Digital thermometerWhy?

    1 digital thermometer: one per home, instead of a mercury thermometer.

  • 1Saline nose dropsWhy?

    1 bottle of saline drops: to have at home; use as your baby's doctor advises.

Hospital bag

  • 1Coming-home outfitWhy?

    1 coming-home outfit: the outfit for the ride home, planned for the weather of the birth month in New York City.

  • 1Hospital bagWhy?

    1 hospital bag: it can be the diaper bag, if everything fits.

For mom

  • 2Nursing braWhy?

    2 nursing bras: one on, one in the wash and one spare; you do laundry every two days.

  • 1Nursing padsWhy?

    1 box of nursing pads: for the first weeks; not every mom needs them.

  • 3Postpartum padsWhy?

    3 packs of postpartum pads: for the hospital and the first weeks at home.

  • 4High-waist cotton underwearWhy?

    4 pairs of underwear: two a day in the first weeks; you do laundry every two days.

  • 2Nursing nightgown or pajamasWhy?

    2 nursing nightgowns or pajamas: for the hospital and nights at home; you do laundry every two days.

Phase 2: Up to 6 months

27 items

Clothes

  • 3Short-sleeve bodysuit3MWhy?

    3 short-sleeve bodysuits: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Short-sleeve bodysuit6MWhy?

    3 short-sleeve bodysuits: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Long-sleeve bodysuit3MWhy?

    3 long-sleeve bodysuits: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Long-sleeve bodysuit6MWhy?

    2 long-sleeve bodysuits: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Sleeper or footie (long sleeves and legs)3MWhy?

    3 sleepers: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Sleeper or footie (long sleeves and legs)6MWhy?

    2 sleepers: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Short-sleeve romper3MWhy?

    2 short-sleeve rompers: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Short-sleeve romper6MWhy?

    3 short-sleeve rompers: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 1Fleece or plush sleeper3MWhy?

    1 fleece sleeper: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 1Fleece or plush sleeper6MWhy?

    1 fleece sleeper: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Footed or pull-on pants3MWhy?

    2 pairs of pants: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Footed or pull-on pants6MWhy?

    2 pairs of pants: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Cardigan or light jacket3MWhy?

    3 cardigans or light jackets: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City.

  • 2Cardigan or light jacket6MWhy?

    2 cardigans or light jackets: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City.

  • 3Socks3MWhy?

    3 pairs of socks: your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Socks6MWhy?

    3 pairs of socks: your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 1Scratch mittens (optional)3MWhy?

    1 pair of scratch mittens: optional, for the first weeks. Short, filed nails are the alternative.

  • 2Knit hat (for going out in the cold)3MWhy?

    2 knit hats: for going out on cold days; your baby will wear size 3M · 0 to 3 months between March and May, with cold weather in New York City.

  • 1Knit hat (for going out in the cold)6MWhy?

    1 knit hat: for going out on cold days; your baby will wear size 6M · 3 to 6 months between May and August, with cold (May), mild (June), and hot (July and August) weather in New York City.

  • 1Sun hat (optional)6MWhy?

    1 sun hat: optional, for walks in the shade in the hot months.

Bath and hygiene

  • 1Soft baby hairbrush (optional)Why?

    1 soft hairbrush: optional.

Diapering

  • 530Disposable diapers1Why?

    530 size 1 diapers (about 4 packs): your baby will likely wear this size for about 10 weeks, with 6 to 10 changes a day.

  • 554Disposable diapers2Why?

    554 size 2 diapers (about 5 packs): your baby will likely wear this size for about 11 weeks, with 5 to 9 changes a day.

Out and about

  • 1StrollerWhy?

    1 stroller: for walks; in the essential list it is optional, because holding and a carrier also work.

Feeding

  • 2Drool bibWhy?

    2 drool bibs: for the drooling phase; you do laundry every two days.

Nursery

  • 1Dresser (optional)Why?

    1 dresser: optional; a closet you already have also works.

Health

  • 1Oral syringe (no needle)Why?

    1 oral syringe: to measure liquid medicine exactly, when prescribed.

Later

14 items

Clothes

  • 3Short-sleeve bodysuit9MWhy?

    3 short-sleeve bodysuits: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Long-sleeve bodysuit9MWhy?

    2 long-sleeve bodysuits: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Sleeper or footie (long sleeves and legs)9MWhy?

    2 sleepers: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Short-sleeve romper9MWhy?

    2 short-sleeve rompers: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 1Fleece or plush sleeper9MWhy?

    1 fleece sleeper: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Footed or pull-on pants9MWhy?

    3 pairs of pants: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 3Cardigan or light jacket9MWhy?

    3 cardigans or light jackets: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City.

  • 3Socks9MWhy?

    3 pairs of socks: your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City, and you do laundry every two days. Your home is heated in winter, so cold months count as mild for clothes worn indoors.

  • 2Knit hat (for going out in the cold)9MWhy?

    2 knit hats: for going out on cold days; your baby will wear size 9M · 6 to 9 months between August and December, with hot (August), mild (September), and cold (October, November, and December) weather in New York City.

  • 1Sun hat (optional)9MWhy?

    1 sun hat: optional, for walks in the shade in the hot months.

Feeding

  • 1High chairWhy?

    1 high chair: for starting solids.

  • 1Baby plate, spoon and cup (optional)Why?

    1 plate, spoon and cup set: optional; your own dishes work if the spoon fits your baby's mouth.

  • 2Feeding bibWhy?

    2 feeding bibs: one per meal of the day, plus one in the wash.

Nursery

  • 1Outlet covers and cabinet latchesWhy?

    1 childproofing kit: before your baby starts to move around.

What the heat changes

Sizes NB and 3M together, balanced amounts, laundry every two days, with a dryer:

PieceHot monthsMild monthsIn the heat
Short-sleeve bodysuits954 more
Short-sleeve rompers633 more
Long-sleeve bodysuits253 fewer
Sleepers253 fewer
Pants242 fewer
Cardigans or light jackets242 fewer
Knit hats022 fewer
Socks (pairs)462 fewer
All pieces23296 fewer

In hot weather a short-sleeve bodysuit or a romper is often the whole outfit. The list still keeps a sleeper or two for cooler nights and air-conditioned rooms, and a cardigan for going out.

Air conditioning is common: in the Energy Information Administration's 2020 survey, 109.51 million of the 123.53 million US homes used air-conditioning equipment 4. The list does not assume it, so in hot months it counts the outdoor heat. At home, what decides the clothes is the room your baby is in, warm or cooled.

Hot days, safely

  • Dress for the room, not for the weather report. Dress your baby for the temperature of the room 5.
  • Watch for signs of heat. Sweating, flushed or hot skin, or a chest that feels hot to the touch are signs that your baby is too hot 5. The CDC lists sweating and a hot chest too 2.
  • Keep the head and face uncovered for sleep, and do not let your baby get too hot 5.
  • Never alone in the car. Do not leave your baby alone in a vehicle, no matter the temperature outside 5.
  • Mosquitoes. No insect repellent on babies younger than 2 months; cover the stroller and the carrier with mosquito netting 6.
For sleep in the heat, fewer layers, never a loose blanket: the crib holds nothing but a fitted sheet 7. Too many layers of clothes and bedding for the room temperature can overheat a baby, and overheated babies are at higher risk of SIDS 5. The cutoffs and amounts on this page are a Cotokim proposal. Checked by the Cotokim team against the sources on this page. It does not replace advice from the health care team that looks after you and your baby.

What this data does not tell you

The temperatures are typical weather, the average of many years, not a forecast, and a heat wave can be hotter. The four cities and the July 15 birth date are examples: your due date and your city change the weeks in each size, and the tool does the math for you.

Frequently asked questions

What should a newborn wear in summer?

Dress your baby for the room 5 and check for signs of heat 5. Cotokim's proposal for the day, in a room at 75 °F (24 °C) or more: One layer: a short-sleeve bodysuit or a romper. In a cooled room at 72 to 75 °F (22 to 24 °C): Short-sleeve bodysuit with light pants, or a light sleeper.

Does my baby need a sleep sack in summer?

Not always. For a room at 75 °F (24 °C) or more, Cotokim's proposal for sleep is: Short-sleeve bodysuit, with or without a 0.5 TOG sleep sack. On hotter nights, the bodysuit alone. The 0.5 TOG figure comes from one sleep sack maker's chart, which lists it for 75 to 77 °F and stops there 3. We found no US government source that uses TOG.

Do I need a sun hat for a newborn?

It is optional on Cotokim's list, for walks in the shade from size 6M.

Do summer babies need fewer clothes?

A few. For sizes NB and 3M together, the hot-month list has 6 fewer pieces than the mild-month one, mostly fewer long sleeves, sleepers and warm layers.

Data sources

Climate normals: NOAA National Centers for Environmental Information, U.S. Climate Normals 1991-2020 1. Our use of material from NOAA and the Energy Information Administration, including links to their websites, does not imply endorsement by NOAA or the Energy Information Administration of Cotokim or its service.

Source credits

Material from the Centers for Disease Control and Prevention (CDC) is available at no charge on cdc.gov. Our use of it, including links to CDC pages, does not mean that the CDC, the U.S. Department of Health and Human Services (HHS) or the U.S. Government endorses Cotokim. Reference to specific commercial products, manufacturers, companies, or trademarks does not constitute its endorsement or recommendation by the U.S. Government, Department of Health and Human Services, or Centers for Disease Control and Prevention.

Courtesy: Eunice Kennedy Shriver National Institute of Child Health and Human Development. Safe to Sleep® is a registered trademark of the U.S. Department of Health and Human Services.

We link to pages of the U.S. Consumer Product Safety Commission (CPSC) in our own words; this does not mean that the CPSC endorses Cotokim.

Brands appear only for the charts of their own products (sizes, packs, TOG). Cotokim has no deal with any brand.

Written by the Cotokim teamChecked by the Cotokim team against the sources on this page, on October 14, 2026

Sources

  1. NOAA National Centers for Environmental Information, U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991-2020). Read on October 13, 2026.
  2. Centers for Disease Control and Prevention (CDC), Providing Care for Babies to Sleep Safely. Read on October 14, 2026.
  3. HALO Innovations, sleep sack maker, What TOG values are SleepSack Wearable Blankets available in?. Read on October 14, 2026.
  4. U.S. Energy Information Administration (EIA), Residential Energy Consumption Survey 2020, Table HC7.1: Air conditioning in U.S. homes, by housing unit type, 2020. Read on October 14, 2026.
  5. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), NIH, Ways to Reduce Baby's Risk (Safe to Sleep). Read on October 14, 2026.
  6. Centers for Disease Control and Prevention (CDC), Mosquito Bite Prevention (United States). Read on October 11, 2026.
  7. U.S. Consumer Product Safety Commission (CPSC), Safe Sleep: Cribs and Infant Products. Read on October 14, 2026.