The best replacement for thermometer is thermostat.

The best alternatives to thermometer are rated as following:
★★★★★  thermostat
★★★★  meat thermometer
★★  regular thermometer
★★  forehead thermometer
★★  digital thermometer
★★  thermocouple
★  candy thermometer
★  ear thermometer
★  thermostat sermon
★  mercury thermometer
★  rectal
★  pyrometer
★  mouth
★  basal body temperature
  ear
  ovulation kit
  mouth thermometer
  oral
  regular digital thermometer
  basal thermometer
  alcohol thermometer
  glass thermometer
  instant read
  underarm
  temporal artery
  basal temperature
  barometer
  meat
  human thermometer
  celsius
  normal thermometer
  thermometer
  temporal thermometer

Your alternative for thermometer is not listed? Suggest!
Speaking about thermometer, one probably shouldn't forget about humidity.

Other search terms related to thermometer and their ratings are:
★★★★★ humidity
★★★★★ hygrometer
★ thermowell
★ clock
You have in mind a companion for thermometer and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of thermometer in all years. Click on graph for more.
thermometer
thermostat
meat thermometer