air humidity sensor for RH 80%+?

I would go for the old DHT22.

When measuring humidity (and temperature as well) inside residential rooms, keep in mind that there is a variation among different areas of the room, so one can never get one single value, but rather a set of 2-3-4-5 or more values.

That being said, I will favor a pair or even three DHT22 placed in key areas of the room instead of one very accurate sensor.

That DHT 22 is influenced by wind, so it is advisable to shield it properly.

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I work with BMP280 and it is very nice, reliable, accurate, but I found difficult to work with related libraries. But that was my case (clone of arduino uno, cone of BMP280).

I did not use a BME280, though.