Tunnel Hill 100K
Race Day Weather
Cool start — fast day potential, big temp swing
A cool 40°F at the start line is ideal for fast times — expect to warm up quickly once you're moving. Temps will climb significantly to 57°F by later miles, so expect fading conditions as the race progresses. Light winds shouldn't be a major factor for pacing.
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Race Info
The Tunnel Hill 100K covers the same Tunnel Hill State Trail out of Vienna, Illinois as the marathon and longer ultra fields, running the full 50-mile out-and-back loop plus an added southern spur before finishing at Vienna City Park. Like the other distances it runs on a crushed-limestone rail-trail bed with a grade under 2 percent, crossing the trail's namesake railroad tunnel twice. The event carries an IAU Bronze Label and is USATF and World Athletics certified.
