• Improved weatherproof enclosure for harsh environments
  • 512K non-volatile flash data storage
  • Up to four Smart Sensors
  • Up to 2 DC voltage or 4-20mA input adapters
  • Logging intervals: 1 second to 18 hours, user-specified interval
  • Operating range:
    • -4 to 122°F (-20 to 50°C) with alkaline batteries
    • -40 to 158°F (-40 to 70°C) with lithium batteries
  • RS-232 via 3.5 mm serial port communications


The HOBO H21-002 Micro Station Data Logger offers reliable monitoring performance at industry leading prices. Designed for stand-alone data logging applications, the 4-channel HOBO Micro Station accepts Onset's full suite of plug-and-play Smart Sensors, and is battery-powered for up to one year.

The H21 supports measurements of temperature, relative humidity, dew point, wind speed, wind direction, rainfall, soil moisture, solar radiation, PAR, barometric pressure, leaf wetness, 4-20mA, voltage input, pulse input, light intensity.


Required Components

These additional components are required for the operation of your product. We strongly advise you to purchase these components unless you already own them or own a suitable alternative.




Please consider these optional accessories.