Experts say rectal temperatures are the most accurate, especially for children under 3 years old. However, many parents are uncomfortable taking rectal temperatures with basic digital thermometers, fearful that they'll insert the probe too far. The best rectal thermometers reduce that anxiety by being easy to insert properly and comfortably.
Accuracy is practically guaranteed when it comes to rectal thermometers. Owners of the best-reviewed Vicks Baby Thermometer V934 (Est. $15) almost universally rave about its accuracy. Some even refer to it as "hospital accurate." Other similar models like the Safety 1st Gentle Read Rectal Thermometer (Est. $10) and Safety 1st Baby's 1st 3-in-1 Thermometer (Est. $5) are equally well reviewed at Amazon.com when it comes to accuracy.
Because rectal thermometers are positively reviewed by owners, the distinguishing feature among them is ease of use. Many parents are wary of traditional stick-style digital thermometers, as it's not clear how far they should be inserted. This makes the Vicks Baby Thermometer V934 a popular option, since its round-handled design and short probe tip make it impossible to insert too far. A handful of other models are designed the same way, though there aren't as many as there are standard digital thermometers. Of course, the downside of this style of thermometer is that it isn't versatile and babies will outgrow it within a year or two.
The Vicks Baby Thermometer V934 gets top marks for its ergonomic design, which has won design awards. It fits comfortably into the palm of the hand, owners say, though it can be prone to rolling off a flat surface due to the round design. The only other frequent complaint editors found is that this model goes through batteries very quickly; it takes an SR41 or LR41, which can be rather inconvenient to find.
Despite the downside, the overwhelming positivity -- among professional and owner reviews -- about the Vicks Baby Thermometer's ease of use makes this model the best pick.