The skies opened up on the second day of the 2017 Martha’s Vineyard Agricultural Fair Friday, with a day of rain and occasional thunderstorms thinning the normally crowded fairgrounds. But fair fans persevered, donning ponchos and huddling under umbrellas to wander the fairground, visit the animals kept dry in the barn, and watch the annual draft horse pull competition. Draft horse teams were unbothered by the weather — in fact, some said, it probably cooled them —as they pulled increasing weights through the rainy ring.