Temperature (see fever). Get to know your thermometer, and then where ever it is taken in the ear, forehead or armpit (not rectal), you will have an idea if your child is hot (>37.5℃ or cold (<35.5℃ and then know how to act. As a general rule for infants, their rooms should be kept around 20 ℃ and they should wear one more layer than you, their parents (big title) are comfortable in.