Weather: DC Half Marathon
Historical weather data for race day in September. Use this to plan your race strategy, clothing, and hydration.
10°C
Temperature
Range: 4°C – 16°C
55%
Humidity
Low — comfortable
35%
Rain Chance
Possible — check forecast
September
Typical race month
Usually on a Sunday
Conditions
Early spring weather with cool temperatures and moderate chance of rain. Runners should expect variable conditions with possible wind from the Potomac River, making layering advisable for comfort during the race.
What to Wear
Light gloves
Useful at the start, tuck away later
Long sleeve or arm warmers
Versatile for cool starts
Hydration Strategy
Before the Race
Normal hydration. Drink to thirst in the 24 hours before. Avoid over-hydrating.
During the Race
Drink at aid stations every 3-4km. Alternate water and sports drink.
After the Race
Rehydrate within 30 minutes of finishing. A drink with electrolytes and some protein helps recovery.
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