# Sensirion SHT3X Weatherproof A temperature and humidity sensor in a weatherproof capsule {.banner-box} _Image Credit: **DF-Robot**_{.image-credit-banner-box} !!! info "Sensor ranges" The weatherproof version uses the same sensor as the [SHT3X](https://docs.smartcitizen.me/knowledge/air/temperature_rel_humidity/Sensirion_SHT3X.md#performance) (SHT31 or SHT35), so the measurement ranges are the same: -40 ºC to 125 ºC and 0 to 100 %rh. Check the datasheet of your probe, since the cable and the housing can limit the operating temperature range. ## Assembly To use this sensor, you'll need a [screw connector to grove adaptor](https://docs.smartcitizen.me/guides/getting-started/third-party-sensors.md#sensors-with-open-leads):  ## Usage and considerations Once connected, the sensor will be automatically detected on boot. Depending on the model, the following metrics are available: | Metric | Shell name | Units | API | |:- |:- |:-: |:- | | Air temperature (SHT31) | `Ext SHT31 Temperature` | ºC | [79](https://api.smartcitizen.me/v0/sensors/79) | | Relative humidity (SHT31) | `Ext SHT31 Humidity` | % | [80](https://api.smartcitizen.me/v0/sensors/80) | | Air temperature (SHT35) | `Ext SHT35 Temperature` | ºC | [224](https://api.smartcitizen.me/v0/sensors/224) | | Relative humidity (SHT35) | `Ext SHT35 Humidity` | % | [225](https://api.smartcitizen.me/v0/sensors/225) | ## Modify temperature and relative humidity offset External sensors offsets can be modified via the `control` command. To check available commands (note that you can change `sht31` or `sht35`): ``` SCK > control ext sht31 Temperature: Available commands: * cal: [float - clear] Sets temperature offset with respect to current offset or clears it ``` To check the offset currently implemented: ``` SCK > control ext sht31 temp cal Current temperature offset: -1.00 (degC) ``` ``` SCK > control ext sht31 hum cal Current humidity offset: 3.50 (rh) ``` !!! info "Default offsets" The default offsets for external sensors are always 0degC and 0%rh. You can always modify them to suit your needs, or revert back to the default with `control temp cal clear` or `control hum cal clear`. To modify, you can issue the `control ext sht31 temp cal` command followed by a the offset to add in float notation (for instance `-10.0`): Check the calibration and read the current value: ``` SCK > control ext sht31 temp cal Temperature: cal Current temperature offset: -1.00 (degC) SCK > read ext sht31 temp Temperature: 25.95 C ``` Set the temperature offset to -10.0 degC. Note that for the previous reading, there was already an offset of `-1.00 degC`, so now the offset will be -11.0 degC: ``` SCK > control ext sht31 temp cal -10.00 Temperature: cal -10.00 SCK > control ext sht31 temp cal Current temperature offset: -11.00 (degC) SCK > read ext sht31 temp Temperature: 15.96 C ``` To revert to the previous value: ``` SCK > control ext sht31 temp cal clear Set default offset: -1.00 (degC) SCK > control ext sht31 temp cal Current temperature offset: -1.00 (degC) SCK > read ext sht31 temp Temperature: 26.09 C ``` Additional, for relative humidity: ``` control ext sht31 hum cal Current humidity offset: 3.50 (rh) SCK > read ext sht31 hum Humidity: 63.06 % ``` ``` SCK > control ext sht31 temp cal Ext SHT31 Temperature: cal Current temperature offset: 0.00 (degC) ``` ``` SCK > control ext sht31 temp cal -2.00 Ext SHT31 Temperature: cal -2.00 Temperature offset set to -2.00 degC ``` ``` SCK > control ext sht31 temp cal clear Ext SHT31 Temperature: cal clear Set default offset: 0.00 (degC) ```