All-Out Fallfest Half Marathon

Westminster, CO, USA · September 19, 2026
partly-cloudy-day60°·72° high·Light·Dry
7
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Race Day Weather

partly-cloudy-day
60°at start
75° high
Breezy
Dry

Comfortable temps, big temp swing, chance of rain

Mild 60°F temps at gun time mean comfortable early miles without overheating risk. Temps will climb significantly to 75°F by later miles, so expect fading conditions as the race progresses. Light winds shouldn't be a major factor for pacing. There's a chance of rain, so have a backup gear plan ready.

partly-cloudy-night8
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partly-cloudy-day8
partly-cloudy-day7
clear-day6
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partly-cloudy-day5
partly-cloudy-day4
partly-cloudy-day5

Pace Calculator

Distance: 13.1mi
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Race Plan

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Weather-adjusted pacing, per-mile terrain splits, fueling timeline with aid stations, packing checklist, carb tracker, spectator guide — all personalized to your goal and race-day conditions.

Race Conditions
Terrain Splits
Nutrition
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T-Minus
Carb Tracker
Spectator Guide
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Race Info

The All-Out Fall Fest Half Marathon in Westminster, Colorado, offers runners a scenic journey along the Big Dry Creek Trail, leading to the picturesque Standley Lake Regional Park. Participants enjoy a mix of paved and gravel paths, with breathtaking views of the Flatirons and a notable stretch near the dam. The event embraces 80s nostalgia, adding a fun and energetic vibe to the race experience.

FAQ

When is the 2026 All-Out Fallfest Half Marathon?

The 2026 All-Out Fallfest Half Marathon will be held on Saturday September 19, 2026.

What is the time limit for the All-Out Fallfest Half Marathon?

The time limit for the All-Out Fallfest Half Marathon is 4 hours.

What will the weather be like for the 2026 All-Out Fallfest Half Marathon?

The forecast calls for a high of 75°F and a low of 57°F with a 49% chance of rain.

Historical Weather

Based on 10 years of data
Avg Temp
60°F
L:50° H:70°
RunScore
8
Conditions
Rain Freq
0%
0 of 10 yrs
Wind2mph
Dew40°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScore
2025
clear-day
55°/72°-
7
2024
clear-day
55°/74°-
7
2023
clear-day
46°/65°-
9
2022
clear-day
50°/70°-
7
2021
clear-day
46°/73°-
8
2020
clear-day
52°/76°-
7
2019
clear-day
53°/69°-
8
2018
clear-day
47°/76°-
8
2017
cloudy
47°/52°-
10
2015
clear-day
49°/70°-
8