Race-day weather · Wyndo for runners
Rock 'n' Roll Washington DC Half Marathon weather
March 20, 2027 · Washington, DC · traditional start around 8:00 AM (America/New_York) — not yet confirmed for 2027. What the start usually feels like, year by year — and a live start-time read once the race confirms its schedule and race week arrives.
Countdown
204 days to race day
The live race-day forecast unlocks 198 days from now, when March 20, 2027 enters the 7-day forecast window. Until then, live hourly data is not available; the history below shows what race morning usually looks like.
The 2027 schedule hasn't been published yet — both the date and start time shown here are carried from earlier editions and aggregators. We'll switch on the live start-time read when the race posts its schedule.
Race-morning weather history
Mid-March Washington DC morning: cool, often ~35–45 °F at 8 AM with wind off the Mall — UNVERIFIED climatology, no station data pulled. 2020 edition CANCELLED (COVID). 2021 ran half + 5K only. Floating recurrence — history rides the hand-listed dates. Wyndo tracks what past editions of the race actually served up at the start hour — temperature, dew point, wind, and rain, and reads the live forecast for the start once the race confirms its schedule and race week arrives.
Scroll sideways to see all columns.
| Year | Start temp | Dew point | Wind | Precip (start hr) | Day's high |
|---|---|---|---|---|---|
| 2026 | 51°F | 48°F | 6 mph | dry | 68°F |
| 2024 | 45°F | 36°F | 5 mph | dry | 65°F |
Each row is the weather at a real past edition's date and this race's current start hour (ERA5 reanalysis at the start line).
Your heat-adjusted goal for the half marathon
The same cited model as the full calculator, pointed at this race: once this race's history is assembled, the typical start-hour conditions plug in here automatically.
Your race-day brief
Skip the taper-week refresh spiral. Email briefs for the Rock 'n' Roll Washington DC Half Marathon: a race-morning outlook when race day enters the 7-day forecast window, updates only when it changes meaningfully, and a final look the day before.
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Race facts
- Start line
- Constitution Avenue NW at 14th Street NW, National Mall. APPROXIMATE: lat is the Nominatim geocode of Constitution Ave NW (38.8921); lon (-77.0316) is 14th St NW, estimated one block east of the Washington Monument geocode (15th St, -77.0352). Start named "Constitution Ave & 14th St NW" in the 2026 MPDC advisory; not surveyed to the arch.
- Traditional start (not confirmed for 2027)
- 8:00 AM (America/New_York) — Half Marathon 8:00 AM ET; 5K 7:30 AM ET (2026 edition, per MPDC traffic advisory & thehotelwashington.com 2026 guide). Start on Constitution Ave NW near 14th St NW (National Mall); finish just west of the U.S. Capitol. Wheelchair/elite offsets not separately verified. Carried forward to 2027.
- Field size
- No defensible half-only finisher count located. Best available: "more than 19,000 registered runners" for the 2024 DC event ACROSS ALL DISTANCES (half + 5K), per Running USA / endurance.biz (runningusa.org …2024-st-jude-rock-n-roll…washington-d-c; endurance.biz/2024/…19000-runners…). That is all-distance REGISTRANTS, not half FINISHERS — do NOT present it as the half field. Scout figure (~13.4k, unclear year) NOT carried. Re-verify live before publishing any number.
- Registration
- open (online registration; St. Jude fundraising/charity entries available)
Wyndo is not affiliated with or endorsed by the Rock 'n' Roll Washington DC Half Marathon (officially the "St. Jude Rock 'n' Roll Running Series Washington DC") or its organizers. Race names are used descriptively to identify the event; schedules and start times belong to the race — always confirm details on the official site. Weather guidance here is informational, never medical advice, and event alert flags on race day belong to the race's own medical team.