www.mammothendurance.com

Washington Island Ultra

Washington County, Wisconsin, United States

calendar_today 23 Jul, 2026 – 24 Jul, 2026

About the Event

Test your human limits in a remote island sanctuary on the Great Lakes. The Washington Island Mammoth Endurance 24 | 36 Hour Relay challenges solo athletes and teams from July 23rd to 25th, 2026, on a unique, loop-based course within Wisconsin's scenic Washington Island State Park. This event redefines toughness with a 0.25-mile swim in crystal-clear Lake Michigan, a fast 9.9-mile rolling bike loop on butter-smooth roads, and a pancake-flat 2-mile run along the shore—all repeatable within a controlled, crew-friendly race village. Designed for maximum safety and involvement, the shorter loops allow for incredible spectator support and a deeply communal atmosphere under vast starry skies. Whether you're chasing a solo ultra-distance or sharing the relay with friends, discover what it truly means to "Be More Human" in this pristine Midwestern wilderness. Claim your spot for an unforgettable endurance festival.

Races Offered

36 Hour

Jul 23, 2026

straighten

Distance — 36H

terrain

Type — Water sports

timer

22:00

24 Hour

Jul 24, 2026

straighten

Distance — 24H

terrain

Type — Water sports

timer

10:00

Weather History

These values represent the 3-year monthly averages for July in Washington County.

thermostat Temperature

17.1° / 26.9°

wb_sunny Feels like

16.8° / 26.8°

light_mode Avg sunshine hours

12h 14m

water_drop Avg rainfall

3.6 mm

ac_unit Avg snowfall

—

air Avg wind speed

10.4 km/h (Light breeze)

opacity Sweat loss rate

High

terrain Course conditions

Hard and dry surface

sunny Max UV Index

Very High (8.0)

humidity_mid Humidity

73.3%

wb_twilight Sunrise

05:27

nightlight Sunset

20:28

About Washington County

Learn more about the host city, Washington County.

Washington County is a county in the U.S. state of Wisconsin. As of the 2020 census, the population was 136,761. Its county seat is West Bend. The county was created from Wisconsin Territory in 1836 and organized in 1845. It was named after President George Washington. Washington County is part of the Milwaukee metropolitan area.