HOBO Temperature/RH Data Logger


  • The HOBO MX2301 is a weatherproof data logger with built-in temperature and relative humidity sensors. Leveraging Bluetooth Low Energy, the logger enables easy, fast set up and data download directly from your mobile device and provides high-accuracy measurements in harsh outdoor environments. Remotely access your data in Onset’s cloud-based HOBOlink software with the new MX Gateway.
  • PART#


The country of origin for this product is the United States. To see the full specifications for this product, please see our product manual found under the documentation tab if available

Temperature Sensor
RangeMX2301A and MX2305 internal sensors: -40 to 70°C (-40 to 158°F)
MX2302A external temperature sensor: -40 to 70°C (-40 to 158°F)
MX2303 and MX2304 external sensors: -40 to 100°C (-40 to 212°F), with tip and cable immersion in fresh water up to 50°C (122°F) for one year
Accuracy±0.25°C from -40 to 0°C (±0.45 from -40 to 32°F)
±0.2°C from 0 to 70°C (±0.36 from 32 to 158°F)
±0.25°C from 70 to 100°C (±0.45 from 158 to 212°F), MX2303 and MX2304 only
Resolution0.04°C (0.072°F)
Drift<0.01°C (0.018°F) per year
RH Sensor (MX2301A, MX2302A only)
Range0 to 100% RH, -40° to 70°C (-40° to 158°F); exposure to conditions below -20°C (-4°F) or above 95% RH may temporarily increase the maximum RH sensor error by an additional 1%
Accuracy±2.5% from 10% to 90% (typical) to a maximum of ±3.5% including hysteresis at 25°C (77°F); below 10% RH and above 90% RH ±5% typical
Drift<1% per year typical
Memory128 KB (63,488 measurements, maximum)
Response Time: Temperature (typical, to 90% of change)Without Solar Radiation ShieldWith RS1/M-RSA Solar Radiation ShieldWith RS3-B Solar Radiation Shield
internal sensor17 minutes in air moving 1 m/sec24 minutes in air moving 1 m/secN/A
Response Time: RH (typical, to 90% of change)Without Solar Radiation ShieldWith RS1/M-RSA Solar Radiation ShieldWith RS3-B Solar Radiation Shield
internal sensor30 seconds in air moving 1 m/sec40 seconds in air moving 1 m/secN/A
Radio Power1 mW (0 dBm)
Transmission RangeApproximately 30.5 m (100 ft) line-of-sight
Wireless Data StandardBluetooth Smart (Bluetooth Low Energy, Bluetooth 4.0)
Logger Operating Range-40° to 70°C (-40° to 158°F)
Logging Rate1 second to 18 hours
Logging ModesFixed interval (normal, statistics) or burst
Memory ModesWrap when full or stop when full
Start ModesImmediate, push button, date & time, or next interval
Stop ModesWhen memory full, push button, date & time, or after a set logging period
Time Accuracy±1 minute per month 0° to 50°C (32° to 122°F)
Battery Type2/3 AA 3.6 Volt lithium, user replaceable
Battery Life2 years, typical with logging interval of 1 minute and Power Saving Mode disabled; 5 years, typical with logging interval of 1 minute and Power Saving Mode enabled. Faster logging intervals and statistics sampling intervals, burst logging, remaining connected with the app, excessive downloads, and paging may impact battery life.
Memory128 KB (63,488 measurements, maximum)
Full Memory Download TimeApproximately 60 seconds; may take longer the further the device is from the logger
DimensionsLogger housing: 10.8 x 5.08 x 2.24 cm (4.25 x 2.0 x 0.88 in.)
External temperature sensor diameter: 0.53 cm (0.21 in.)
External temperature/RH sensor diameter: 1.17 cm (0.46 in.)
External sensor cable length: 2 m (6.56 ft)
Solar radiation shield bracket: 10.8 x 8.3 cm (4.25 X 3.25 in.)
WeightLogger: 75.5 g (2.66 oz) Solar radiation shield bracket: 20.4 g (0.72 oz)
MaterialsAcetal, silicone gasket, stainless steel screws
Environmental RatingNEMA 6 and IP67
CE CompliantThe CE Marking identifies this product as complying with all relevant directives in the European Union (EU). This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules.

  • Convenient wireless setup and download via Bluetooth Low Energy (100-foot range)
  • Retrieve data in hard-to-reach locations
  • Visual alarms alert you to out-of-range conditions
  • Compact, weatherproof housing with built-in mounting
  • View current data in real time with Onset’s free HOBOmobile app
  • Share downloaded data easily from your mobile device
  • Accuracy: +/- 0.2C° and +/- 2.5% RH

In what environment does this data logger operate?

This data logger operates in an outdoor environment.

What measurements does this data logger support?

The MX2301A data logger supports the following measurements: Relative Humidity, Temperature and Dew Point