The alfalfa seems to be a little more forgiving moisture wise over the grass/upland hay.
Part of the reason the alfalfa is more forgiving is most alfalfa is conditioned which breaks the stems to let the moisture out so the plant moisture stays more consistent.  Drop alfalfa without a conditioner and the leaves are dry after a day or two but is takes another 2-3 days to dry the stem out.

I think lately the summers in Minnesota are just staying humid during the “drying” days. Feels dry but it’s not. Stem moisture.
I would say the exact opposite based on NOAA data.  The past few years hitting humidity sub 35% that makes the hay dry faster and a lot of guys bragging about 'dry hay in a day' but the reality is with grass hays it still takes time for moisture to migrate out of the stem.