An infant has a much more delicate system than an adult or even an older child, so he can become too hot very quickly. When weather or clothing is making your baby warm, take off a layer of his clothes and adjust the temperature in the room. If he doesn't cool down within a few minutes or has other symptoms such as diarrhea, call his doctor right away.
Crying Out Loud
An infant uses crying as a way to communicate many things. If her heat level is making her uncomfortable, she will likely start crying. Narrow down the list of possibilities that are upsetting her to determine if she's too hot. If she has a clean diaper, has eaten recently and isn't due for a nap, try removing her blanket or a layer of clothing. If she doesn't stop crying soon after, she wants something else. Play with her or walk her around the room.
Taking your baby's temperature is the most accurate way to determine if he has a fever. Take his temperature rectally if he's under 3 months old, since this is the most accurate method for babies that young. Your baby has a fever if his temperature is over 100.4 degrees Fahrenheit. A fever can be a sign of a health problem such as infection or pneumonia, so call his pediatrician immediately if his temperature is above 100.4 degrees.
Feeling your baby's skin can tell you quickly how she's feeling. You should have an idea what your baby's skin feels like when she's happy and comfortable, so you'll be able to tell if she is hotter than usual. Press your wrist against your baby's forehead or kiss her there. Your skin is delicate on your lips and wrists so you'll be able to tell if she feels hotter than normal. Feeling her ears and fingers may also give you an indication of her temperature.
Signs of more serious problems caused by overheating may be harder to spot. If your baby has heat exhaustion, he may be very thirsty or sleepy, and his skin may feel moist and cool. If he becomes even more overheated, he may be lethargic, vomit, have a rapid pulse or have red, dry skin. These signs, combined with a temperature of over 103 F, all signal heat stroke, which is a life-threatening condition. A baby with these signs needs immediate medical attention.