Pack or skip
Insect repellent for Washington DC in September
Verdict
Pack it
Warm (81°F) plus 8 rainy days = mosquito conditions.
Why
Washington DC in September averages highs of 81°F, lows of 64°F, 8 rainy days.
That climate means insect repellent earns its space in the bag. Warm (81°F) plus 8 rainy days = mosquito conditions.