# Adafruit HTU21D-F Temperature & Humidity Sensor ## Overview ![](https://cdn-learn.adafruit.com/assets/assets/000/101/434/medium800/temperature___humidity_HTU_top.jpg?1618430995) It's summer and you're sweating and your hair's all frizzy and all you really want to know is why the weatherman said this morning that today's relative humidity would max out at a perfectly reasonable 52% when it feels more like 77%. Enter the **HTU21D-F Temperature + Humidity Sensor** - the best way to prove the weatherman wrong! ![](https://cdn-learn.adafruit.com/assets/assets/000/101/435/medium800/temperature___humidity_HTU_back.jpg?1618431002) This I2C digital humidity sensor is an accurate and intelligent alternative to the much simpler [Humidity and Temperature Sensor - SHT15 Breakout](https://www.adafruit.com/products/1638) It has a typical accuracy of ±2% with an operating range that's optimized from 5% to 95% RH. Operation outside this range is still possible - just the accuracy might drop a bit. The temperature output has an accuracy of ±1°C from -30~90°C. If you're looking to measure temperature more accurately, we recommend the [MCP9808 High Accuracy I2C Temperature Sensor Breakout Board.](https://www.adafruit.com/products/1782) ![](https://cdn-learn.adafruit.com/assets/assets/000/101/437/medium800/temperature___humidity_HTU_top_angle.jpg?1618431111) Such a lovely chip - so we spun up a breakout board that includes the Filtered version (the white bit of plastic which is a PTFE filter to keep the sensor clean), a 3.3V regulator and I2C level shifting circuitry. This lets you use it safely with any kind of microcontroller with 3.3V-5V power or logic. ![](https://cdn-learn.adafruit.com/assets/assets/000/101/436/medium800/temperature___humidity_HTU_top_header.jpg?1618431094) To get you going fast, we spun up a custom made PCB in the[**STEMMA QT** form factor](https://www.adafruit.com/?q=stemma%20qt%20sensor "STEMMA QT form factor"), making them easy to interface with. The [STEMMA QT connectors](https://learn.adafruit.com/introducing-adafruit-stemma-qt/what-is-stemma-qt) on either side are compatible with the [SparkFun Qwiic](https://www.sparkfun.com/qwiic) I2C connectors. This allows you to make solderless connections between your development board and the HTU21Ds or to chain them with a wide range of other sensors and accessories using a [**compatible cable**](https://www.adafruit.com/?q=stemma%20qt%20cable). [QT Cable is not included, but we have a variety in the shop](https://www.adafruit.com/?q=stemma+qt+cable&sort=BestMatch). Each order comes with one fully assembled and tested PCB breakout and a small piece of header. You'll need to solder the header onto the PCB but it's fairly easy and takes only a few minutes even for a beginner. Info: ![](https://cdn-learn.adafruit.com/assets/assets/000/017/113/medium800/sensors_1899-01.jpg?1401846030) - [Next Page](https://learn.adafruit.com/adafruit-htu21d-f-temperature-humidity-sensor/pinouts.md) ## Primary Products ### Adafruit HTU21D-F Temperature & Humidity Sensor Breakout Board [Adafruit HTU21D-F Temperature & Humidity Sensor Breakout Board](https://www.adafruit.com/product/1899) It's summer and you're sweating and your hair's all frizzy and all you really want to know is why the weatherman said this morning that today's relative humidity would max out at a perfectly reasonable 52% when it feels more like 77%. Enter the **HTU21D-F Temperature +...** In Stock [Buy Now](https://www.adafruit.com/product/1899) [Related Guides to the Product](https://learn.adafruit.com/products/1899/guides) ### Adafruit HTU21D-F Temperature & Humidity Sensor Breakout Board [Adafruit HTU21D-F Temperature & Humidity Sensor Breakout Board](https://www.adafruit.com/product/3515) It's summer and you're sweating and your hair's all frizzy and all you really want to know is why the weatherman said this morning that today's relative humidity would max out at a perfectly reasonable 52% when it feels more like 77%. Enter the **HTU21D-F Temperature +...** No Longer Stocked [Buy Now](https://www.adafruit.com/product/3515) [Related Guides to the Product](https://learn.adafruit.com/products/3515/guides) ## Related Guides - [My Mini Race Car](https://learn.adafruit.com/my-mini-race-car.md) - [I2C Addresses and Troublesome Chips](https://learn.adafruit.com/i2c-addresses.md) - [Adafruit MLX90640 IR Thermal Camera](https://learn.adafruit.com/adafruit-mlx90640-ir-thermal-camera.md) - [CLUE Vertical Garden Weather Visualizer](https://learn.adafruit.com/clue-vertical-garden-weather-visualizer.md) - [Soil Moisture Sensor with Circuit Playground Express and MakeCode](https://learn.adafruit.com/soil-moisture-sensor-with-circuit-playground-express.md) - [ESP-NOW in CircuitPython](https://learn.adafruit.com/esp-now-in-circuitpython.md) - [Modern Replacements for DHT11 and DHT22 Sensors](https://learn.adafruit.com/modern-replacements-for-dht11-dht22-sensors.md) - [Calibrating Sensors](https://learn.adafruit.com/calibrating-sensors.md) - [Adafruit HDC302x Precision Temperature & Humidity Sensor](https://learn.adafruit.com/adafruit-hdc3021-precision-temperature-humidity-sensor.md) - [IoT Air Quality Sensor with Adafruit IO](https://learn.adafruit.com/diy-air-quality-monitor.md) - [Monitor Your Greenhouse with a No-Code Environmental Sensor](https://learn.adafruit.com/monitor-your-greenhouse-with-a-no-code-environmental-sensor.md) - [Compost Friend!](https://learn.adafruit.com/compost-optimization-machine.md) - [Adafruit AM2320 Sensor](https://learn.adafruit.com/adafruit-am2320-temperature-humidity-i2c-sensor.md) - [DHT11, DHT22 and AM2302 Sensors](https://learn.adafruit.com/dht.md) - [Adafruit TE MS8607 PHT Sensor](https://learn.adafruit.com/adafruit-te-ms8607-pht-sensor.md)