@sealyons I made a test with the calibrated temperature mesurement device: Calibrated device: 21.7 21.8 DS18B20: 21.9 21.9 DHT22: 21.8 21.9 SI7021: 21.7 21.8 BMP085: 22.4 22.5 BME280: 21.8 21.9 Besides the BMP085, all devices were on the spot = within 1 digit variance. That status was stable for 5 hours testing. Only the BMP085 was always ~0.6 °C above, but still that at the limits of it's spec.

@radec Maybe also a wrong setting/connection of the multimeter. Many of them have separate ports for current and all other signals.