This is DHT22 is a digital temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air, and spits out a digital signal on the data pin (no analog input pins needed). 

Compared to the DHT11, this sensor is more precise, more accurate and works in a bigger range of temperature/humidity.

Features

• 3 to 5V power and I/O.
• 2.5mA max current use during conversion (while requesting data).
• Good for 0-100% humidity readings with 2-5% accuracy.
• Good for -40 to 125°C temperature readings ±0.5°C accuracy.
• 0.5 Hz sampling rate. 

Temperature and humidity sensor arduino code and how to connect.

DHT22 Temperature and humidity sensor datasheet.