It’s finally summertime, and if your little one is still under 1, there can be a lot to remember about how to keep them cool, comfortable and protected in the heat and sun. Babies can’t regulate their temperatures like adults or communicate when they’re feeling too warm, so it’s important to know what to look for and plan ahead. From spotting the signs of overheating to choosing the right sunscreen and more, Children’s Hospital Colorado pediatrician Kaitlin Whelan, MD, answers the top questions you might have about how to keep your baby cool in the summer so you can navigate the warm weather months with confidence.

How should I dress my baby during the day and for sleep in the summer?

Loose, lightweight, breathable cotton in light colors is the best option for your baby to wear in the summertime. Long sleeves and pants also offer sun protection but avoid anything sheer. For time spent outside, use a wide-brimmed hat or UV sunglasses, as well. If your baby won’t keep these accessories on, prioritize shade and sun-protective clothing.

For sleep, it’s best to keep your house between 68 degrees Fahrenheit and 70 degrees Fahrenheit, so babies are cool enough to be comfortable wearing their pajamas with a swaddle or sleep sack. Be sure to stop using the swaddle once your baby can roll. To stop your house from heating up during the day, close the curtains in your baby’s bedroom and consider using a fan (out of reach of little fingers).

When can babies be in the sun, and how should I plan for sun exposure?

It’s best to avoid extended outdoor time when temperatures are above 90 degrees Fahrenheit or during peak sun hours (from around 10 a.m. to 2 p.m.) Sun is most damaging at midday and in high elevation places, such as Colorado. Also keep in mind the UV rays will be present on cloudy days and reflect off water or snow, even if you’re not in direct sunlight. Avoiding sunburn in a child’s early years is especially important. Research shows sunburns before the age of 15 are more strongly associated with increased risk of melanoma and skin cancer later in life. If you're outside, take breaks in the shade or indoors every 20 minutes to cool down. Some shade options include:

1. A pavilion
2. A breathable tent with mesh sides for airflow
3. A small umbrella
4. Your stroller’s built-in shade canopy. Avoid draping a blanket over your stroller since that can trap in heat.

Never leave your baby alone in a car to prevent sun exposure.

Can I use sunscreen on my baby? What kind is safe?

For babies under 6 months, avoid using sunscreen and keep them shaded and in protective clothing instead. If you absolutely cannot avoid sun exposure for your little one at this age, you can use mineral-based sunscreen (zinc oxide or titanium dioxide) on small areas. Test a small amount first on your baby’s skin to make sure it doesn’t irritate them.

For babies 6 months and older, use mineral-based, broad-spectrum sunscreen with SPF 30 or higher anytime you go outside in the summer months. Apply the sunscreen 15 to 30 minutes before sun exposure and reapply every two hours — especially if you are sweating or in water. Generally, mineral sunscreens are less irritating than chemical sunscreens for babies’ skin. Dr. Whelan says to opt for lotion sunscreen over spray sunscreen at this age to avoid your child breathing any sunscreen in. If spray is your only option, spray some on your hand first, and then apply to your child.

Despite your best efforts, sometimes little ones still end up with a sunburn. You might need to bring them to your doctor or healthcare team if they are under 1 year old and their sunburn starts to blister.

What are the signs of overheating, dehydration or heat-related illnesses?

Watch for the signs of overheating, dehydration and heat-related illnesses, such as heat exhaustion. These can include:

1. Being unusually sleepy
2. Refusing to eat or drink
3. Feeling hot or sweaty
4. Having fewer wet diapers

If you start to notice any of these signs, bring your baby into a cooler space and offer extra fluids. You can also offer a cool rag — but not too cold because you don’t want them to shiver. If their clothes are sweaty from being outside in the heat, change them into fresh clothes once they are inside so they don’t get cold.

If these symptoms are accompanied by a fever over 104 F in the hot weather, you should seek emergency care.

What’s the safest way for my baby to stay hydrated in the heat? Can my baby drink water?

We don’t recommend that babies under 6 months drink water. At this age, breastmilk or formula offers all the hydration they need. Instead, offer feedings more frequently in the hot weather. For babies over 6 months, small sips of water are OK, but they shouldn’t replace milk or formula as the main source of hydration.

Can my baby go swimming?

Generally, Dr. Whelan recommends babies start getting comfortable in water around 6 months old, once they have good head control and can safely wear sunscreen. Always test the water temperature with your hand — it should feel warm, not cold. Never leave your baby unattended around water, even for a moment, including bathtubs. According to American Academy of Pediatrics guidance, babies can wait to start formal swim lessons until after the age of 1.

Learn more summer safety tips from our experts.

Enjoy summertime

Remember that babies can’t easily regulate their temperature or communicate with us when they’re getting too hot. But that doesn’t mean you can’t enjoy outdoor time with them in the summer. Keeping your baby cool, shaded and hydrated will ensure that you can make the most of these fun and sun-filled months.