ENDURrun Marathon
Race Day Weather
Warm day, adjust pace early
Runners will face a temperature range from 61°F at the start to 77°F by the finish, with humidity averaging 72%. Light winds from the NW will be a non-factor, but with the heat, it's crucial to adjust pace and hydrate frequently. A throwaway layer may be useful during the pre-race warm-up as the feels-like temperature drops to 60°F.
Pace Calculator
Get forecast alerts for ENDURrun Marathon
We'll text or email you when the forecast shifts — so you can adjust gear, pacing, and strategy. Max one per day.
Race Info
The ENDURrun Marathon is Stage 7 of The ENDURrun, a multi-day stage race held in Ontario's Waterloo Region since 2003 and organized by Run Waterloo. The marathon stage runs five 8.439 km loops on a mostly paved bike path at RIM Park in Waterloo and is a certified Boston Marathon-qualifying course (certification ON-2022-018-PTBA). The full seven-stage Ultimate, the only format that includes the marathon, was announced in December 2024 as biennial, but the 2027 Race Roster listing schedules the marathon stage for August 15, 2027, after the August 16, 2026 edition. A separate ENDURrun Sport event, capped at the half marathon, ends on the same day.
