The Best Weather Sources for Runners

We've all been there. Checking multiple weather sources in the week leading up to the big race, trying to figure out what to wear and if the conditions will be favorable. Even on a daily basis, a reliable weather forecast is critical to optimizing each run and can answer questions like:

Should I carry water with me?Will the ground be icy?Should I wear a hat to keep the rain out of my eyes?Are conditions safe?Should I adjust my pace due to wind, heat and/or humidity?What should I wear?I've...