ring up the seller and ask them what the weather is like there- if the horse is a tad spooky they'll prob try to rearrange, but it would be good to see it in adverse weather- after all you don't always get to ride in the sunshine at home. last time i bought a horse is was pouring down with rain- so bad that my video camera got wrecked. i bought the horse tho- he had a very no nonsense attitude to working in the rain!
Don't see why not (provided still safe to drive there and sellers still happy for viewing). I 1st saw Sparks in gale force wind and driving rain. I didn't ride as had my arm in sling and was only going to be the sharer (then). However my friend tried her like her, and brought her the following week having taken her instructor out for a 2nd look and me hacking her out as arm was the out of its sling. TBH the weather wasn't great the following week either, but it was December!!
Call and check with owners - I would go and if I liked horse would arrange to go back on a quieter day if I didn't get to try all the things I wanted 'coz of weather. At least owner knows you are genuinely interested.
I went to try my boy in Dec 07 in torrential rain and howling gale! He was 5 and behaved beautifully, and I figured if I liked him in that weather then he'd got to be the right horse! One year on and I'm sure I made the right decision.
I went to see my boy in good weather and tried him out, Arranged to hack him out on my own on another day, Weather was foul windy and rain and still went. That ride was what convinced me he was the one for me. Behaved beautifully, even when a small branch came down and landed on his withers!