 Upper 90s to low 100s for high temperatures for today through Wednesday as the next boundary will eventually bring a drop in temperatures for Thursday. But before that, the excessive heat does continue. Heat index values 105 to 110 starting tomorrow. Heat index today will stay around 102. And not much heat relief at night due to the urban heat island. The district forecast lows around 79 to 80 degrees in upper to mid 70s outside of the Beltway.