Enviro weather sensor accuracy

Playing with an Enviro Weather. I have installed the 0.0.9 firmware.

I have noticed that the temp and humidity are very in-accurate when running on USB power. This appears to be due to the electronics heating up a bit when it is constantly powered. When allowed to cool to ambient (power off) and then turned on you can see the temp reading rising to 3-4 degrees higher that the room. For testing I have the sample time set to 1 minute. At the same time the humidity reading drops to show about 15% below the actual reading. I have several other sensors in the same place as the Enviro and they are generally withing 0.5 degree and +/- 3% RH. Using a thermal camera you can see that the sensor chips are getting some heat bleed from the RP2040. They really would benefit from being further from the RP2040 I think.

The project I am working on was going to power the Enviro board using USB power as I do not need to use batteries. Now I am going to use a 5V buck convertor to convert the power and connect it to the board via the plug which should fix the heating issue.

That, IMHO, is an age old problem, and not just with Pimoroni hardware.
There is almost always a tradeoff when trying to make something small, and keep the cost of manufacture down. It’s even more of an issue if you have an LCD display in the mix.
It’s one reason I use the breakouts when possible. Less heat transfer from the other electronics. I have several Enviro clones here, Pico with BME280 etc breakouts added and on qwicc cables.