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Sometimes, the first clue that your baby is sick is a fever (most pediatricians define that as a thermometer reading above 100.4 degrees Fahrenheit). A fever in babies 4 months or younger is an emergency, so accuracy is key. Here, the very latest thermometer ratings, based on accuracy, and expert shopping advice from Consumer Reports Best Baby Products.

features to look for:

speed reading: Some thermometers claim to display a reading in as fast as five seconds. When you're trying to take a wiggle worm's temperature, you don't have much time to get the job done. Yet, for our money, a 20 to 60-second reading is fast enough.

positioning gauge: Some rectal thermometers feature an indicator that lets you know it isn't inserted too far- a definite plus for a peace of mind

sound effects: A thermometer that beeps when it's done is useful; that way, you won't leave it in any longer than necessary

brains: Look for a thermometer that "remembers" the previous temperature taken and displays it when you push a button. That function can be handy, especially in the middle of the night, when you're sleep-depreived and trying to assess in which direction your baby's feaver is going

Rectal: Tops for Temps
You can take a baby's temperature many ways -- by mouth or ear, on the forehead, or under the arm -- but the American Academy of Pediatrics considers rectal readings to be the most precise in children younger than 3.

Your best bet: Get an inexpensive digital thermometer that can be used rectally. Use a disposable probe cover each time, or clean the end with rubbing alcohol and rinse with cool water after each use. Once your baby has her first birthday, your pediatrician may allow you to use a different temp-taking method; ask.

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