Humidity is not just about rain. It’s a combination that makes humidity go up and down, not just rain. Also depending on where your Air is situated can influence hugely it’s readings.
I live in a region known to be very humid, bit like Vietnam, no rain in weeks and still I can have nights gong near 95% …
We’d need to know a bit more of where your Air lives, above grass , above stone … Calibration routine ran yesterday but didn’t apply any change for you .