Three GPIO wires and a cheap sensor are enough to read live temperature and humidity on your Pi .
The DHT22 connects directly to GPIO without extra chips, and the guide covers both live readout and logging to a CSV you can open in a spreadsheet. Note: a few readers hit LGPIO library snags; solutions are in the comments and the tutorial addresses them. Not useful if you need readings faster than once every 2 seconds.
What would you do with live temperature and humidity data from your Pi — dashboard, alerts, something else?