From WUSA9:
Games 3, 4 & 5* - Washington, DC
In DC, our forecast isn't perfect. We'll be watching a developing low pressure system that brings a wet 24 hours to the DC area in the middle of the home stretch. Models don't 100% agree on the timing of this. Right now, we think Friday's game will squeeze by dry and the rain holds off until early Saturday morning. Saturday's game would be miserable with rain and temps in the 50s. This could lead to a delay or postponement. Sunday looks colder but dry.
Disclaimer: this is a forecast for 7+ days out. It WILL change. But this can help to give you an idea of what you could experience at the games or any outdoor watch parties.