Race-day weather · Wyndo for runners
Colfax Marathon weather
May 16, 2027 · Denver, CO · scheduled start 6:00 AM (America/Denver). What the start usually feels like, year by year — and a live start-time read once the race is inside the 7-day forecast window.
Countdown
263 days to race day
The live race-day forecast unlocks 257 days from now, when May 16, 2027 enters the 7-day forecast window — a start-time read for the scheduled 6:00 AM start. Until then, live hourly data is not available; the history below shows what race morning usually looks like.
Typical start temp
46°F
median of 20 years
A warm year
48°F
75th percentile start temp
Rain at the start
5%
1 of 20 measured years
Race-morning weather history
High-altitude race (~1,609 m) with a 6:00 AM start to beat Front Range heat; May in Denver swings from near-freezing starts to 80F+ afternoons with occasional late-season snow. 2020 cancelled and 2021 ran in October — exclude/flag both in May history; pre-2008 editions used a different course. Wyndo tracks what this calendar slot has actually served up at the start hour — temperature, dew point, wind, and rain — including the years when weather canceled or disrupted the race, and reads the live forecast for the start once race week arrives.
Median start temp
46°F
p75 (a warm year): 48°F
Median dew point
38°F
at the start hour
Rain at the start
5%
1 of 20 measured years
Warmest start
52°F
in 2024
Scroll sideways to see all columns.
| Year | Start temp | Dew point | Wind | Precip (start hr) | Day's high |
|---|---|---|---|---|---|
| 2026 | 51°F | 44°F | 3 mph | dry | 65°F |
| 2025 | 47°F | 43°F | 3 mph | dry | 67°F |
| 2024 | 52°F | 42°F | 8 mph | dry | 78°F |
| 2023 | 48°F | 41°F | 5 mph | dry | 75°F |
| 2022 | 49°F | 37°F | 6 mph | dry | 79°F |
| 2021 | 48°F | 45°F | 5 mph | dry | 61°F |
| 2020 | 44°F | 38°F | 1 mph | dry | 75°F |
| 2019 | 41°F | 38°F | 5 mph | dry | 55°F |
| 2018 | 43°F | 42°F | 6 mph | dry | 61°F |
| 2017 | 40°F | 31°F | 5 mph | dry | 66°F |
| 2016 | 42°F | 35°F | 3 mph | dry | 57°F |
| 2015 | 46°F | 33°F | 6 mph | dry | 64°F |
| 2014 | 45°F | 41°F | 7 mph | dry | 84°F |
| 2013 | 50°F | 40°F | 4 mph | dry | 67°F |
| 2012 | 41°F | 37°F | 6 mph | dry | 75°F |
| 2011 | 37°F | 36°F | 5 mph | 0.2 mm | 52°F |
| 2010 | 38°F | 34°F | 5 mph | dry | 66°F |
| 2009 | 47°F | 36°F | 6 mph | dry | 78°F |
| 2008 | 45°F | 33°F | 7 mph | dry | 82°F |
| 2007 | 49°F | 41°F | 7 mph | dry | 76°F |
Slot climatology: each row is the weather at this race's usual calendar slot and start hour (ERA5 reanalysis at the start line) — including years when the edition was canceled or moved. A computed slot date is not a claim the race ran that day.
Your heat-adjusted goal for the marathon
The same cited model as the full calculator, pointed at this race: the median start-hour conditions this calendar slot has served up — climatology, not a forecast.
Your race-day brief
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Race facts
- Start line
- City Park, Denver — east side of Ferril Lake (official course-overview wording). Coordinates APPROXIMATE, mapped from that description. City Park start/finish since 2008; the 2006 inaugural ran a different Aurora course.
- Scheduled start
- 6:00 AM (America/Denver) — Official 2027 marathon page: 6:00 AM MT Sunday; the Marathon Relay shares the gun; half 6:30 from the same start after the marathon clears; the Urban 10 Miler starts from a DIFFERENT venue (RMCAD, Lakewood, ~7:45-9:00). No wheelchair/elite gun published on reachable pages; wave detail unverified (official info pages 404 during site transition).
- Field size
- 2026 marathon finishers per FindMyMarathon (aggregator — official results live behind a JS-only timing app). Weekend totals far larger (~25,000 across all races in 2024).
- Registration
- open (2027 registration opened Aug 2026; no lottery/qualifier)
Wyndo is not affiliated with or endorsed by the Colfax Marathon (officially the "Denver Colfax Marathon") 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.