So, very dry wood - 2-3 years seasoning, sitting outside without top cover. I was thinking of putting some of it in the woodshed (open on 3 sides), but then it rained on Monday, and will rain again tomorrow. No problem, we get almost no rain in July and August, so it can wait. But I wanted to clear a little room for more wood processing. So the question is - how long after a rain would you wait before putting seasoned wood away? Is poking a few pieces with a moisture meter on the outside an adequate check?
If the shed is open on 3 sides, I wouldn't worry one bit about a little rain, especially with summer being here. As long as its getting some air circulation, a little bit of surface moisture should dry out pretty quick. Regarding MM testing, what I'm usually looking for is problems with my top covering, which can lead to 'wet spots' in the stack. So I'll usually "spot check" a few on the outside, then I'll re-split and check the inside to get the "real" reading. From there, I just check the outsides, as long as it's the same species, age, and stacking location. If I'm getting the same reading on the outside, I'm pretty confident that I'd get the same readings on the insides, without having to split every piece.
It would depend upon how much rain you got and what the air has been like since the rain. I have moved wood into the shed right after a short rain and never worried. If it were a 24 hour rain, I'd simply wait until the outside of the wood is dry, which is usually no more than 24 hours and then put it indoors. As for a moisture meter, as I've stated in the past, I have no need of one. And for sure if the wood is 2-3 years in the stack, why would you need a MM?
It rained the last couple days here on the "wet" side of the state as well, but they are calling for upper 70's next week, so I am sure it well be hotter in E.Wash. So why not wait till end of next week to move it. It would be fine by then.