My AirVisual Pro is reporting temperatures higher or lower than the actual ambient outdoor temperature. What could be causing this?

In a controlled testing environment, the AirVisual Pro was tested between temperatures from -20°C up to +60°C. There were no deviations detected more than ~+1°C and -1.5°C. In addition, the different measurement intervals (continuous [10s], three minutes and 15 minutes) seem not to influence temperature measurement accuracy. The testing was also done with the screen turned off.

IQAir recommends checking the settings of the device and ensure that the screen is switched off, and to increase the evaluation/testing time to 10 minutes.
If the settings are checked, and the issue still occurs, IQAir recommends sending in the device for evaluation and repair.

Please keep in mind the operating temperature of AVP devices is defined on our website: 32 to 104 °F (0 to 40 °C).

You can find more information about the AirVisual Pro's temperature range here: What temperature range can the AirVisual Pro function within? | IQAir