The temperature sensor in PurpleAir devices comes pre-calibrated by the manufacturer, and currently, there is no method for manually recalibrating it. However, if you’re seeing temperature readings that seem higher than expected, there are a few common reasons—and some helpful solutions.
Why Are the Temperature Readings Higher?
The temperature sensor in PurpleAir devices is located inside the sensor housing, near internal components such as the Wi-Fi module. These components generate heat during operation, which causes the air inside the sensor to be hotter and drier than the surrounding ambient air. As a result:
- Temperature readings may appear slightly elevated
- Humidity readings may appear lower than actual outdoor conditions
How to View Corrected Temperature Data
The PurpleAir Map includes a corrected temperature layer that adjusts for this internal heat bias. To ensure you’re seeing corrected data:
- Go to map.purpleair.com
- In the Data Layer list, select “Temperature °C”
- This view includes a correction formula that typically aligns more closely with true ambient temperatures
More on this correction:
A Note on Temperature and Humidity Corrections
Check for Firmware-Related Issues
If you are already using the corrected “Temperature °C” data layer and still see abnormal readings, your sensor may be running firmware version 7.04, which has been known to affect temperature accuracy for some users.
To check your firmware version:
- On the map, scroll to the bottom of the Data Layer list
- Select the “Firmware Version” layer to view your sensor’s current firmware
If your device is on version 7.04 and you believe it’s affecting your data:
- You can request a rollback to version 7.02 by emailing us at contact@purpleair.com
Please note:
- Rolling back to 7.02 may improve temperature accuracy, but it may also reduce the accuracy of VOC readings, which are experimental
- Once rolled back, the device will remain on 7.02 until you request an update
For Extremely High or Stuck Readings
If your sensor consistently reports unusually high temperature readings, well beyond typical indoor or outdoor values, even after accounting for internal heating and firmware adjustments, it’s possible that the temperature sensor may be damaged or malfunctioning. In these cases, the component may need to be replaced. Please reach out to our support team with your sensor details, and we’ll help diagnose the issue and can provide a quote for a new temperature sensor if needed.