Mystery Mountain 12M

Chatsworth, GA, USA · October 17, 2027·
partly-cloudy-day46°·52° high·Light·Dry
10
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Race Day Weather

partly-cloudy-day
46°at start
65° high
Light
Dry
Your goal
0:00:00

Cool start — fast day potential, big temp swing

A cool 46°F at the start line is ideal for fast times — expect to warm up quickly once you're moving. Temps will climb significantly to 65°F by later miles, so expect fading conditions as the race progresses. Light winds shouldn't be a major factor for pacing.

Race day forecast available in 341 days
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Pace Calculator

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Race Plan

Get your personalized Mystery Mountain 12M race plan

A mile-by-mile breakdown of where your time goes, weather-adjusted splits, fueling timeline with aid stations, packing checklist, carb tracker, spectator guide, all built around your goal and race-day conditions.

Race Pace
Weather Splits
Nutrition
Gear & Packing
T-Minus
Carb Tracker
Spectator Guide
Race Band

Race Info

The 12M is a trail race at Fort Mountain State Park in Chatsworth, Georgia, on the same Sunday morning as the marathon. It starts with a flat loop around the park lake, then climbs by the rocky, rooty Big Rock trail onto the single-track Gahuti trail, which runs cambered and rocky just below the summits of Cohutta and Fort Mountains. Runners make a narrow loop around the top of the mountain past the legendary rock wall, descend and come back to the lake by the other side of the Big Rock trail, and finish with another lap around the lake. The climbing continues on the way down, so the course never gives much rest.

Race weekend

Sunday, October 17
8:00 AMMarathon (26.2 mi)
8:00 AM12M (12.0 mi)

FAQ

When is the 2027 Mystery Mountain 12M?

The 2027 Mystery Mountain 12M will be held on Sunday October 17, 2027.

What is the time limit for the Mystery Mountain 12M?

The time limit for the Mystery Mountain 12M is 6 hours.

What will the weather be like for the 2027 Mystery Mountain 12M?

The forecast calls for a high of 68°F and a low of 47°F with a 6% chance of rain.

Historical Weather

Based on 18 years of data
Avg Temp
55°F
L:51° H:60°
RunScore
8
Conditions
Rain Freq
6%
1 of 18 yrs
Wind2mph
Dew50°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScoreResults
2026
partly-cloudy-day
42°/51°-
10
2025
partly-cloudy-day
51°/62°-
8
2024
clear-day
51°/63°-
8
2023
clear-day
39°/53°-
10
2022
partly-cloudy-day
42°/51°-
10
2021
clear-day
63°/71°-
4
2019
cloudy
54°/58°Light
9
2018
cloudy
57°/62°-
7
2017
partly-cloudy-day
62°/72°-
4
2016
clear-day
53°/60°-
9
2015
cloudy
58°/60°-
7
2014
clear-day
63°/70°-
4
2013
clear-day
52°/63°-
7
2012
cloudy
60°/63°-
7
2011
clear-day
55°/63°-
7
2010
clear-day
47°/58°-
9
2009
clear-night
38°/50°-
10
2008
clear-night
33°/45°-
10