Dew was important in ancient Israel, especially in August and September. There was no rainfall during the summer, but there was heavy dew from winds blowing in from the Mediterranean, which would have given the crops enough moisture to prevent the ripening grain from wilting and being scorched in the heat. If that dew had not come, the harvest would have been pitiful.1
10 Therefore the heavens above you have withheld the dew, and the earth has withheld its produce.