DENVER — While a weather change is exected to bring rain and cooler temps to the Denver metro over the next few days, the rain should mostly hold off during Sunday morning for the Colfax Marathon.
The Colfax Marathon weekend is back with thousands of runners expected in the two-day event, happening Saturday and Sunday. Other races like the half-marathon and the Urban 10 Mile are still available, and spots for the marathon are filling up. More info. and how to register, here.
This year marks the 20th anniversary of the Colfax Marathon through Denver and Lakewood.
Here's a bit of what you should know:
📅 Dates & Events
- Marathon weekend runs Saturday, May 16, and Sunday, May 17, 2026.
- Saturday: 5K at 9:00 a.m. (City Park).
- Sunday: Full Marathon, Half Marathon, Urban 10 Miler, and Marathon Relay starting at 6:00 a.m. (City Park).
- Boston Marathon qualifier.
📍 Start/Finish
- All Sunday races start and finish in Denver’s City Park.
- Courses include runs through Empower Field at Mile High (twice), Denver Fire Station #1, and even a mile through the Denver Zoo.
Here's the Sunday hourly forecast from Denver7 meteorologist Stacey Donaldson
🏅 Course Highlights
- Scenic routes past Denver landmarks: Sloan’s Lake, Colfax Avenue, downtown Denver, and historic Lakewood.
- Over 40 on-course attractions — live music, cheer stations, and themed relay handoffs.
- Aid stations every mile to two miles.
🚧 Road Closures
- Expect Sunday morning street closures along Colfax Avenue, downtown, City Park areas, and Sloan’s Lake; details available on the “Traffic Closures” page at runcolfax.org.
"D, H and L light rail (Sunday, May 17, only):
- D and H lines will not serve Colfax at Auraria Station through the Downtown Loop stations on Stout and California streets
- D and H lines will continue to serve 10th-Osage Station, and will reroute to serve Auraria West Station, Empower Field at Mile High Station, Ball Arena-Elitch Gardens Station and Union Station
- The L Line will not be in service during the event, and customers are encouraged to use bus Route 43 as an alternative
- No impacts to RTD rail service are expected to occur on Saturday, May 16
- Customers should expect delays on D, E, H and W lines during the event due to increased rail traffic at Union Station. Plan for extra travel time to/from Downtown
Bus routes:
May 17 only: the following bus routes will be temporarily detoured in many areas, and will be allowed to cross the marathon route when possible: 0, 1, 6, 8, 9, 10, 12, 15, 15L, 16, 19, 20, 24, 28, 30, 38, 40, 43, 44, 48, 51, 52, 76, 83L, ART, FREE
Customers using routes affected by the marathon should expect delays and detours, which may affect scheduled connecting bus and rail trips.
Check the RTD website before traveling for schedules and to plan a trip"
For the May 17 race day, RTD is accepting Colfax Marathon 2026 race bibs, 6 a.m.-2 p.m. as valid fare payment on the following rail lines and bus routes:
Rail lines: W Line
Bus routes: 15, 15L, 16"
And finally, you can find information on Lakewood road closures here.
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