here in Huntsville,AL --
yesterday= 44F/42F == 6am dry/wet
today = 28/27
typical -- any season
80%RH = 'low'
--
actually at the Meridianville AL airport, which is close to me

so, don't tell everyone to open their crawl vents to allow dry air to circulate!
&
do carefull evaluation for attic venting, & vapor barrier placement!