Not just here - hot and dry - but everywhere. Sometimes it is too much rain rather than none at all. Too hot. Not hot soon enough. Run a Google search for "weather + farmers markets.
Today an Ohio news station, on of many, reports on the weather impact on farmers' market
"Delay in crops: extreme weather is a growing concern for farmers who make money off summer crops. The spring rain and summer heat has affected sweet corn and a few other crops.
Farmers have to take advantage of what mother nature provides. The amount of rain and heat not only impacts what you may see at a farmers' market but when you may see it there as well."