EE181-L Air Temperature and Relative Humidity Sensor
Accurate, Rugged
Ideal for long-term, unattended applications
weather applications water applications energy applications gas flux and turbulence applications infrastructure applications soil applications


The EE181 is a rugged, accurate air temperature and relative humidity (RH) probe that is ideal for long-term, unattended applications. It includes a proprietary coating on the RH element that increases the life of the element and protects it from dirt, dust, salt, or other contaminants. A 1000 Ω PRT measures air temperature for the -40° to +60°C range. For optimum results, the EE181 should be recalibrated annually.

Benefits and Features

  • Well-suited for long-term, unattended applications
  • Accurate, rugged, reliable
  • Outstanding long-term stability
  • Wide operating temperature range
  • User cleanable
  • Compact and easily interchangeable
  • Low power consumption
  • Compatible with most Campbell Scientific dataloggers


EE181-L Air Temperature and Relative Humidity Probe with protective cap
EE181-L Air Temperature and Relative Humidity Probe with protective cap
EE181-L Air Temperature and Relative Humidity Probe with protective cap
EE181-L Air Temperature and Relative Humidity Probe
Side view of EE181-L and RAD10E (sold separately)
Section view of RAD10E and EE181-L (sold separately)


Measurement Description Temperature, relative humidity
Signal Type/Output Analog voltage
Supply Voltage 7 to 30 Vdc (typically powered by the datalogger’s 12 V supply)
Average Current Consumption < 1.2 mA
Filter Description 30 μm pore size, stainless-steel mesh
Startup Time 2 s
Housing Body Material Plastic
Housing Classification IP65
Field Replaceable Chip or Recalibrate Recalibrate
Operating Temperature Range -40° to +60°C
Sensor Diameter 2.1 cm (0.83 in.)
Length 16.0 cm (6.3 in.)
Weight 290 g (10.2 oz) with 5 m cable

Air Temperature

Sensing Element 1000 Ω Platinum Resistance Thermometer (PRT)
Measurement Range -40° to +60°C
Storage Temperature Range -40° to +80°C
Output Signal Range 0 to 1 Vdc
Accuracy ±0.2°C (at +23°C)

Relative Humidity

Sensing Element Capacitance
Measurement Range 0 to 100% RH (non-condensing)
Output Signal Range 0 to 1 Vdc
Temperature Dependence Typically 0.03% RH/°C
  • -NOTE- Accuracy specifications include hysteresis, non-linearity, and repeatability.
  • ±(1.3 + 0.003 • RH reading) % RH (at -15° to +40°C, 0 to 90% RH)
  • ± 2.3% RH (at -15° to +40°C, 90 to 100% RH)
  • ± (1.4 + 0.01 • RH reading) % RH (at -25° to +60°C)
  • ± (1.5 + 0.015 • RH reading) % RH (at -40° to +60°C)


Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.

Data Loggers

Product Compatible Note
CR1000 (retired)
CR3000 (retired)
CR800 (retired)
CR850 (retired)

Additional Compatibility Information

Sensor Mounts

When exposed to sunlight, the EE181 must be housed in a 10-plate solar radiation shield. Campbell Scientific recommends the MetSpec RAD10E, which uses a double-louvered design that offers improved sensor protection from driving rain, snow, and insect intrusion. This shield also has lower self-heating in bright sunlight combined with higher temperatures (> 24°C [~75°F]) and low wind speeds (< 2 m s-1 [~4.5 mph]), giving a better measurement.

The EE181 will work with R. M. Young 10-plate radiation shields (41003-5 or 41003-5A), but these shields require a special adapter (pn 28415) to accommodate the sensor girth.

The RAD10E and 41003-5 attach to a crossarm, mast, or user-supplied pipe with a 2.5 to 5.3 cm (1.0 to 2.1 in.) outer diameter. The 41003-5A radiation shield attaches to a CM500-series pole or a user-supplied pole with a 5.1 cm (2.4 in.) outer diameter.

Case Studies

Utah: Flux Stations
The Utah Geological Survey, supported by the Utah Division of Water Rights, has constructed more
Union of the Comoros: Establishment of Four Weather Stations for Better Resilience to Climatic Hazards
As part of the United Nations Development Programme's (UNDP) Crisis Prevention and Resilience Building component, more

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