Diablo Trail Marathon

Clayton, CA, USA · September 6, 2026
clear-day64°·85° high·Light·Dry
8
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Weather
Course
Race Info
FAQ
History

Race Day Weather

clear-day
64°at start
87° high
Light
Dry

Comfortable temps, big temp swing

Starting at 64°F, heat will be a factor from the gun — go out conservative and stay on top of hydration. Temps will climb significantly to 87°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 34 days
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Race Info

Mount Diablo provides spectacular views of the San Francisco Bay Area and surrounding valleys. The 4 mile course is relatively flat and fast within Mitchell Canyon. The longer events are mountainous and very scenic. Source

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Course Map

Course Map Unavailable

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FAQ

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When is the 2026 Diablo Trail Marathon?

The 2026 Diablo Trail Marathon will be held on Sunday September 6, 2026.

What will the weather be like for the 2026 Diablo Trail Marathon?

The forecast calls for a high of 85°F and a low of 58°F with a 0% chance of rain.

Historical Weather

Based on 13 years of data
Avg Temp
85°F
L:61° H:85°
RunScore
6
Conditions
Rain Freq
15%
2 of 13 yrs
Wind11mph
Dew48°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScore

2025 Diablo Trail Marathon

Clear conditions throughout the day.

2025
clear-day
64°/82°-
7

2024 Diablo Trail Marathon

Clear conditions throughout the day.

2024
clear-day
60°/94°-
8

2023 Diablo Trail Marathon

Clear conditions throughout the day.

2023
clear-day
58°/87°-
8

2022 Diablo Trail Marathon

Partly cloudy throughout the day with rain.

2022
rain
63°/72°Light
7

2021 Diablo Trail Marathon

Clearing in the afternoon.

2021
cloudy
60°/81°-
8

2019 Diablo Trail Marathon

Clear conditions throughout the day.

2019
clear-day
67°/92°-
7

2018 Diablo Trail Marathon

Clear conditions throughout the day.

2018
cloudy
58°/79°-
8

2017 Diablo Trail Marathon

Clear conditions throughout the day.

2017
clear-day
68°/103°-
6

2016 Diablo Trail Marathon

Clearing in the afternoon.

2016
cloudy
61°/82°-
8

2015 Diablo Trail Marathon

Clear conditions throughout the day with afternoon rain.

2015
partly-cloudy-day
65°/83°Light
7

2014 Diablo Trail Marathon

Clear conditions throughout the day.

2014
cloudy
58°/82°-
8

2013 Diablo Trail Marathon

Clear conditions throughout the day.

2013
clear-day
56°/81°-
8

2012 Diablo Trail Marathon

Clear conditions throughout the day.

2012
clear-day
54°/82°-
8

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Free guidesMarathon Fueling Guide·Carb Loading Guide·Race Morning Guide·Race Day Gear Guide·Pacing Strategy Guide·Mental Strategy Guide

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