• Dew point range: 32 to 122°F (0 to 50°C)
  • Humidity range: 0 to 100%
  • Humidity accuracy: ±3%
  • Temperature range: -4 to 158°F (-20 to 70°C)
  • Temperature accuracy: ±0.9°F (±0.5°C)
  • Wall, desktop, or tripod mount
  • Programmable audible and visual alarms
  • Optional calibration with 33% RH and 75% RH calibration bottles
  • LCD screen shows humidity, temperature, date, and time

What's in the Box

  • USB cable
  • Universal AC adapter
  • 4 AA batteries


The Extech 42280A temperature and humidity datalogger is designed to continuously monitor temperature and humidity to maintain ideal storage conditions in environments such as laboratories and cleanrooms, and to ensure comfort in hospitals and other indoor working facilities. The USB, included with the device, allows a user to connect the datalogger to their PC for further analysis. Users can then export to a PDF or Excel spreadsheet to see data and graphs on their PC. 

The Extech 42280A has an internal sensor that measures humidity between 0 to 100% with an accuracy of ±3% and temperatures from -4 to 158°F (-20 to 70°C) with an accuracy of ±0.9°F (±0.5°C). The sensor also measures dew points from 32 to 122°F (0 to 50°C). Additional features include programmable audible and visual alarms, an LCD screen showing humidity, temperature, date, and time, as well as a wall, desktop, or tripod mount.