April can be a tricky time to race a marathon because, although the dates of marathons are usually chosen to coincide with cool temperatures, you may have the unfortunate luck of getting an extremely hot and humid race day. Running during those conditions in April is even more difficult than doing it in July or August because, after training in the cold all winter, most runners are not prepared to run in the heat and humidity.
If you're gearing up for a big race and the forecast is calling for hot weather, here are some tips:
Stay well-hydrated. Make sure you're well-hydrated during the week leading up to the race, especially on route to your race destination and once you get there.
Re-evaluate your goals. On a race day, take weather conditions into account. Brutal heat and humidity mean you should scale back your performance goals. Don't try to beat the heat.
Dress lightly. Light-colored, loose-fitting clothing will help your body breathe and cool itself naturally. Tight clothing restricts that process, and dark colors absorb the sun's light and heat. Light colors reflect the sun from your skin.
Cool off with water. At the water stops, take two cups of water - one to drink and one to dump on yourself. Splashing water on your head and body will cool you down quickly and have a lasting effect as the water evaporates from your skin. Just try to keep your feet dry, since wet feet can lead to blisters.