Temperature calibration?

I have several Ruuvi sensor boards bought 2018 and 2019. Temperatures varies ±1 C degrees in between different units when placed on same spot. Is there a change to calibrate these?

I use Android app only and FW is what was when arrived.

± 1 C between 2 units is within the limits of sensor accuracy. The temperature value is compensated with a complex formula, so a static offset at one point could mean that the value is erroneous at some other temperature.

I am annoyed these small deviations as well, especially since I set up Grafana to show the values, these deviations really jump into picture. Here is a picture of pressure values where tags are in same spot.

Is it possible to do calibration to values somewhere in software, like in Grafana? I could adjust this with adding +/- 1 type of equations ontop of the sensor reading. Or allow us even to make software adjustments these in mobile app at some point, as the quality of the sensor data seems to vary?

Grafana supports math operations, you can add something like +0.5 to the data.