Diablo Trail Marathon

Clayton, CA, USA • September 6, 2026
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Race Day Weather

clear-day
61°
89° high
Breezy
Dry

Warm afternoon, adjust pace wisely

Runners will face a temperature rise from 64°F to 89°F, with average humidity at 44% and a dew point of 51°F. Winds will be from the WSW at 12 mph, gusting to 24 mph. Given the heat, it's crucial to adjust pacing and ensure proper hydration throughout the race.

Race day forecast available in 163 days
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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

Area Map

Course Map

Course Map Unavailable

We don't have course map data for Diablo Trail Marathon yet. If you have a GPX file (or other format) for this race, we'd love to add it!

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When is the 2026 Diablo Trail Marathon?

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

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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