The DHT22 goes by several names. The other common name is the RHT22. The data sheet says that it will run from 3.3V to 6V which makes it ideal for Arduino application. Temperature range is -40°C to 80°C with 0% to 100% relative humidity.
The Si7021 is a low-cost, easy-to-use, highly accurate, digital humidity and temperature sensor. This sensor is ideal for environmental sensing and data logging and perfect for build a weather stations or humidor control system.
This is a stainless steel, Type-K Thermocouple probe. A thermocouple works by taking two wires made of dissimilar metals, connecting them at the two ends, and making a temperature gradient between one end and the other (a ‘hot’ end and a ‘cold’ one).