About 1630, s5 TRH fan was being turned off. We upped the fan threshold current level from 80 to 150ma and now the fan is going (reading ~110ma). T and RH have been reading fine all the time, though who knows how good the signal is with no aspiration. We'll have to visit this site, with the idea of replacing this fan (and will have to reset the current threshold back at that time).
P.S. It died soon after we did this, getting above 150 as well. So, I've just reset to 80mA and we have it on the list to be replaced.
P.P.S. Note that with low overcast skies, the radiation error will be small anyway, so these data still can be used.
P.P.P.S. Now that it has been several hours since the rain ended, I tried a reset (^R) again. This time, the fan is back at about 38mA and stayed up. Also, I didn't see much of a change (if any) in temperature after it restarted. So...we might say that it was just the rain and now works, but I'm still suspicious.