Temperature & Humidity Loggers

These loggers are manufactured by Onset Computer Corporation, also known as HOBO Loggers.

Temperature & Relative Humidity Loggers

HOBO Pro v2 Loggers

The HOBO Pro v2 data loggers are weatherproof loggers that provide high accuracy Temperature and Relative Humidity measurements in a wide range of outdoor environments.

  • High-accuracy measurements
  • Small-diameter, external sensor for measuring in tight spaces (U23-002, U23-003, U23-004)
  • Weatherproof housing for use in outdoor or condensing environments
  • Replaceable RH sensor provides superior recovery from condensing conditions
  • Optic USB interface for fast and reliable download
Internal Temp/RH


HOBO U23-001 Temp/RH logger

-40° to 70° C (-40° to 158° F)

Battery Life: 3 years (typical)

External Temp/RH


HOBO U23-002 External Temp/RH logger

-40° to 70° C (-40° to 158° F)

Cable Length: 184 cm (6ft)

Battery Life: 3 years (typical)

2x External Temp


HOBO U23-003 2x External Temp logger

-40 to 100 C (-40 to 212 F)

Cable Length (x2): 184 cm (6ft)

Battery Life: 3 years (typical)

Internal & External Temp


HOBO U23-004 Temp/External Temp logger

Internal: -40° to 70° C (-40° to 158° F)

External: -40° to 100° C (-40° to 212° F)

Cable Length: 184 cm (6ft)

Battery Life: 3 years (typical)

Base-U-4 or U-DTW-1 is required with this logger.

U23 data offload diagram

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U23 Brochure

Temperature-only Loggers

HOBO pendant temperature loggerHOBO Pendant Loggers

The Pendant logger is a low-cost, weatherproof and waterproof temperature data logger that is designed for short or long-term monitoring applications. These loggers will record the temperature and allow you to download a file to your computer for further review and analysis. They communicate using USB through an infrared pendant base station (standard base station and waterproof shuttle are also compatible). There are also data shuttles that allow you to collect data in the field without a laptop.

The US-002 models also record light intensity.

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Pendant Brochure

There are a variety of models available:

hobo-pendant-temperature-alarm-data-logger-64k-ua-001-64_100 hobo-pendantsup-sup-temperature-light-data-logger-64k-ua-002-64_100 hobo-pendantsup-sup-event-data-logger-ua-003-64_100
UA-001-08 UA-001-64 UA-002-08 UA-002-64 UA-003-64
8k Memory 64k Memory 8k Memory 64k Memory 64k Memory
Temperature Temperature/Light Temp/Event
-4° to 158° F Air
-4° to 122° F Water
0-30k footcandles
1 yr battery

HOBO water temp pro v2 temperature loggerHOBO Water Temp Pro v2 Logger

(Model: U22-001)

The HOBO Pro V2 water temperature logger is designed for durable underwater temperature monitoring and recording. Some features include: 12-bit resolution, rugged case design and non-volatile EEPROM memory. A protective boot is available for added protection and extremely rugged environments.

These loggers require an infrared base station or waterproof shuttle. The loggers are water proof to 120 meters (400 feet).

  • Temperature Range (water): -40° to 122° F in Water
  • Temperature Range (air): -40° to 158° in Air
  • Accuracy: 0.38° F from 32° to 122° F
  • Memory Size: 42,000 Measurements
  • Battery: 6 year typical life
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Water Temp Pro v2 Brochure

HOBO U12 deep ocean temperature loggerHOBO U12 Deep Ocean Temperature Logger

(Model: U12-015-03)

The HOBO U12 Deep Ocean temperature data logger is designed to track water temperatures in the most extreme ocean enviornments. Built with a virtually indestructible Titanium housing, the logger can withstand corrosive water and exposure to extreme temperature and pressure at depths of up to 11,000 meters (36,000 feet).

Data is read via a direct USB connection and requires HOBOware Pro software. (A USB data shuttle is also available).

  • Maximum Depth: 11,000m (36,080 ft)
  • Temperature Range: -40° to 125° C (-40° to 257° F)
  • Accuracy: 0.38° F from 32° to 122° F
  • Memory Size: 42,000 Measurements
  • Battery: 6 year typical life
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U12 Brochure