(Radio Iowa) – Iowans may need to rethink their weekend outdoor plans, as forecasters say the entire state will be under an Extreme Heat Watch from Saturday afternoon through Sunday night. Meteorologist Brooke Hagenhoff, at the National Weather Service, says Saturday will be the first full day of summer, and the hot-and-muggy weather will arrive right on time. “We’re looking at excessive heat,” Hagenhoff says. “Really the main time-frame for the hottest conditions Saturday and Sunday with the heat index maybe surpassing 105 degrees in many cases.”

Even after the sun goes down on Saturday night, she predicts there will be little relief from the steamy conditions. “We’re looking at overnight low temperatures that could be record warm,” Hagenhoff says. “We’re looking at low temperatures in the upper 70s and with that humidity still around, overnight, it may still feel like the mid to upper 80s.”

A storm front may arrive Monday which she says may knock down the heat. As for the weekend ahead, she suggests you drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.