The Adafruit Si7021 is a temperature and humidity sensor from Silicon Labs with a PTFE filter for protection against dust and contaminants. It provides ±3% relative humidity accuracy over 0–80% RH and ±0.4 °C temperature accuracy from −10 to +85 °C, all communicated over a simple I2C interface.

The breakout includes a 3.3 V regulator and level shifting, making it compatible with both 3.3 V and 5 V power and logic. Some light soldering is required to attach the included header.

Key Features

• Relative Humidity Accuracy – ±3% RH (0–80% RH range)
• Temperature Accuracy – ±0.4 °C (−10 to +85 °C range)
• PTFE Filter – Protects the sensor from dust while allowing accurate humidity readings
• I2C Interface – Simple two-wire communication
• 3.3 V / 5 V Compatible – Onboard voltage regulator and level shifting

Also Consider

• SHT40 Sensor – Newer Sensirion sensor with ±1.8% RH accuracy and STEMMA QT connectors
• SHT45 Sensor – Highest precision with ±1.0% RH and ±0.1 °C accuracy

Ideal For

• Environmental monitoring and weather stations
• HVAC and climate control systems
• Indoor comfort monitoring
• Data logging projects

Package Contents

• 1× Adafruit Si7021 Temperature & Humidity Sensor Breakout (with PTFE filter)
• 1× Header strip (soldering required)

Resources

• Adafruit Si7021 Guide (Arduino & CircuitPython)