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Outdoor Temperature Sensor
(lemmy.world)
Home Assistant is open source home automation that puts local control and privacy first. Powered by a worldwide community of tinkerers and DIY enthusiasts. Perfect to run on a Raspberry Pi or a local server. Available for free at home-assistant.io
I use this one: https://www.aqara.com/us/temperature_humidity_sensor.html
If you already have ZigBee setup it's easy to use these, if not maybe look for something else.
I also use one of these outside with a 3D printed case. Still going strong after about 18 months!