For those going tonight:
Capital Weather Gang's NatCast has 'This game will have the feel of a game played anytime from early June to early September. Very pleasant mid-to-upper 70s for the balance of the game.' - partly cloudy, between 79-81 at first pitch, 74-76 in ninth inning, 5% chance of precip.
Also if you're Metro-ing to/from the match, expect it to be a bit more crowded - tonight is also Caps-Bruins playoff Game 3.