In keeping with my usual obsession with the weather at long events, I've been checking out forecasts leading up to Marine Corps Marathon in two weeks.
The long-term forecast isn't out for race day yet, but it's still looking pretty warm for at least the next 10 days: http://www.intellicast.com/Local/Forecast.aspx?location=USDC0001
70*F to 82*F for the highs, lows only down to 50-53*F.
Here's the climatological data on race day, just in case you were wondering - yeah, if it's full sun and no wind and 65 degrees, that can feel pretty darned hot on those 4-lane concrete roads when you're trying to run:
Day: 28 Oct
Record High 83°F
Record Low 25°F
Normal High 65°F
Normal Low 40°F
Normal Precip 0.11in
Normal Snowfall 0in
I'm betting on a warm race day. I'm going minimalist again - my standard shorts and my sleeveless jersey that I wore for a couple other PRs this year. I'll wear a throwaway long-sleeve tshirt to the start, and then run with as little as I can after that. If I get cold, I'm not running hard enough. :-) I'll also have to wear a waist-pack too to hold all my tons of Clif Bloks (26-30, 1 per mile plus a few extra) and salt caps (~20 if I use Endurolytes) and my phone. I might leave a jacket and my phone with baggage check, though.
I do like several of the MCM clothing items that are being sold this year - I might spend a little money at the expo!! http://www.brooksrunning.com/cat.php?k=70546