This lovely sensor for Silicon labs has +-3% relative humidity measurements with a range of 080% RH, and +-0.4 C temperature accuracy at a range of -10 to +85 C. Great for all of your environmental sensing projects. It uses I2C for data transfer so it works with a wide range of microcontrollers.

Key Features:

3% relative humidity measurements with a range of 0 80% RH, and 0.4 degree C temperature accuracy at a range of -10 to +85 degree C
I2C for data transfer
A 3.3V regulator and level shifting
3.3V or 5V power & logic
A PTFE filter to keep the sensor clean, that’s the white flat thing on top
Product Dimensions: 17.8mm x 15.3mm x 3.0mm / 0.7″ x 0.6″ x 0.1″
Product Weight: 1.0g / 0.0oz

Relevant Resources:
Check out our awesome tutorial for how to use it with Arduino or CircuitPython
Datasheets, schematics, EagleCAD files, Fritzing object and more in the tutorial