This module utilizes the DHT22 which is a combined humidity and temperature sensor assembly. Note that AM2302 is just another name sometimes used for the DHT22 and you may see this marking on the module.
The DHT22 sensor is capable of reading humidity over the full range of 0 to 99.9% with an accuracy of +/- 2% and temperature over the range of -40 to 125°C with an accuracy of +/- 0.5°C. The humidity accuracy increases to +/-5% at temperature extremes.
The device does have a minimum sampling time of 2 seconds so the sensor cannot be polled more often than every 2 seconds or bad data may be retrieved.
