Originally Posted by BabyCAP

Your pressure will increase due to the high temps. Then at night the temp decreases and tire pressure drops. The sensor may pick this up and issue a warning. What you want to do is re-set the warning and then drive immediately after re-set. This way the sensor calibrates to the pressure when you did the re-set.

FYI - I am in DC with hot and humid temps. I parked in airport lot for a weekend trip (visiting Cali !!!!) When I return it is raining and overcast. Drive off lot and get a warning. Check pressure with gauge and all good. Re-set button and have been good since.

IMO It's your amazing West coast weather that may be the culprit. You had a heat wave last week or so and that might be the cause.