Early Saturday morning, an estimated 15,000 runners from near and far will gather near RFK Stadium for the National Marathon and National Half Marathon. What does the weather have in store for both runners and spectators?

In a word: cold. But here some details about exactly what to expect:


Prerace, 5-7 a.m.: 31-35

Opening gun, 7 a.m.: 34-36

9 a.m.: 37-39

11 a.m.: 41-43

1 p.m.: 44-46

Sky conditions: Partly to mostly cloudy

Wind: From the north at 5-10 mph

What to wear? For specators, it’s easy - bundle up - with winter coats, scarves, hats and gloves. Race participants should dress based on their own experiences and level of comfort running in similar conditions.

Note: A few rain and/or snow showers are possible (40% chance) Friday night into pre-dawn Saturday before the race. But amounts, if any, will be very light and should not impact the course.

Jason is the Washington Post’s weather editor and Capital Weather Gang's chief meteorologist. He earned a master's degree in atmospheric science, and spent 10 years as a climate change science analyst for the U.S. government. He holds the Digital Seal of Approval from the National Weather Association.