I have been experimenting with the Indegogo A3 version where the temperature output is mostly higher than expected. uRADMonitor 82000137
type:8 hw:105 sw:135
Attached is a graph of A3 temperatures and fairly accurate real temperatures taken near the A3 outside the house away from wind sun.
It appears that from the temperature range of -20c to about 5c the temperature correction follows a rather linear path.

The formula I use to correct the temperature from the graph is

Corrected temperature = 1.456*A3 temperature -5.67

eg. if the A3 temperature was indicating -5c the real temperature would be 1.456*-5 -5.67= -7.28-5.67= -12.95c

If your A3 is mounted outside give the temperature correction formula a try and see if it works for you.

David