How early do you start checking the weather for race day?

I know Accuweather's extended forecast is 15 days instead of the normal 10, so that's when I start paying attention.

The problem with checking the weather that early is that the forecast 15 days from now almost always changes.

A few days ago, Accuweather said it would be raining in Philly the entire weekend of my race. Of course, that made me more than a little nervous. Running 26.2 miles is hard enough. The thought of running 26.2 miles in the cold rain made me want to curl up into a little ball and cry.

This morning when I checked the weather report again, that rain had moved to earlier in the week and now Accuweather says there will be some clouds, but mostly sunny with a high of 44. Sounds like pretty good racing weather to me.

Of course, we're still 11 days out from the race and the forecast could change a lot between now and then.

Next week, I'll be paying much closer attention to the weather. It will determine what I need to pack for my trip to Philly and it will help me figure out an appropriate race day outfit.

Do you check the weather for your race as soon as it's available in the extended forecast? Do you wait until closer to race day, when the prediction is probably more accurate?