I've never heard that you need to store hatching eggs cool and humid. May I ask where you got the information (not doubting you, just curious to see if I'm doing it wrong
) .
We store hatching eggs on the counter in the kitchen, which runs about 78 degrees in the summer, with low humidity due to the AC. We have 100% hatches under a broody, even with eggs that are 10+ days old. <shrug>
I think it may depend on how precious the eggs are, how much trouble you go to. I did put some fancy hatching eggs from show-quality birds into my basement for three days before setting them when they arrived scrambled. Don't know if it was the lower temperature or not (our basement runs around 30% humidity and 68 degrees) but we did get a decent hatch from those eggs--9 of 12 hatched under a broody.