While hanging out in the North Bay during the atmospheric river event of a couple weeks ago I was killing time indoors during the heavy rain and monitoring ATC. Numerous airline flights went missed on the RNAV approach to 14 at STS and had to divert to airports like OAK and SMF. The non-precision approach to 14 has fairly high minimums so you're not going to be able to get in there when the weather is bad.

I did enjoy the one MQ flight that was asked for a PIREP and reported to STS Tower after landing that they broke out "right at minimums." I've heard that before

Anyway, to put things in perspective, "standard" old fashioned ILS minimums are 1/2 mile visibility and a decision height of 200' above runway touchdown zone elevation, tons of exceptions apply but that's the old school rule-of-thumb. Landing south on runway 14 at STS you need 1 3/8 miles visibility and minimum descent altitude is 600' MSL / 478' above touchdown zone.

Don't book a flight to STS in bad weather unless you don't mind the extra segment from Oakland or Sacramento!