Capital Weather Gang NatCast has 'We've seen some pretty nice weather at Nationals Park this season, but this evening's uncomfortably hot and humid air breaks the trend. Keep the fluids flowing and you should be OK.' with first-pitch temperature of 90's, down to 80's by ninth inning, 5% chance of precip.
Weather forecasts also warn of heat index in 100-105 range - rather unhealthy. Somewhat on the fence about going tonight myself, though the prospect of seeing Strasburg try and pull us out of this tail-spin remains attractive (tomorrow, similar weather is expected, but one of my seat-mates bought my ticket for tomorrow night so I'll be enjoying full air-con with Slowes/Jageler for the finale - plus less pricey adult beverages too of course).
...and yet...can you believe that in the first half of the 20th century, not only were all baseball matches played during the day, but people actually wore suits and ties to the ballpark? Regardless of the weather??