All-Out Fallfest Half Marathon

Westminster, CO, USA • September 19, 2026
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Race Day Weather

clear-day
53°
80° high
Light
Dry

Cool start, warming trend ahead

Runners will face a temperature rise from 56°F at the start to 79°F by the finish, with low humidity at 35%. Winds will be light at 6 mph from the SE, with occasional gusts up to 26 mph. It’s advisable to start conservatively and adjust pacing as temperatures climb.

Race day forecast available in 176 days
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Pace Calculator

Distance: 13.1mi
0:00:00
HH:MM:SS
Pace
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Weather Adj.
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Common Goals:

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. Source

Area Map

Course Map

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When is the 2026 All-Out Fallfest Half Marathon?

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

Historical Weather

Based on 9 years of data
Avg Temp
78°F
L:54° H:78°
RunScore
8
Conditions
Rain Freq
11%
1 of 9 yrs
Wind5mph
Dew34°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScore

2025 All-Out Fallfest Half Marathon

Clear conditions throughout the day with rain.

2025
clear-day
55°/74°-
8

2024 All-Out Fallfest Half Marathon

Clear conditions throughout the day.

2024
clear-day
59°/87°-
8

2022 All-Out Fallfest Half Marathon

Partly cloudy throughout the day with afternoon rain.

2022
clear-day
55°/76°-
8

2021 All-Out Fallfest Half Marathon

Clear conditions throughout the day.

2021
clear-day
51°/88°-
7

2020 All-Out Fallfest Half Marathon

Clear conditions throughout the day.

2020
clear-day
58°/83°-
8

2019 All-Out Fallfest Half Marathon

Becoming cloudy in the afternoon.

2019
clear-day
56°/75°-
8

2018 All-Out Fallfest Half Marathon

Clear conditions throughout the day.

2018
clear-day
53°/85°-
8

2017 All-Out Fallfest Half Marathon

Partly cloudy throughout the day with rain.

2017
cloudy
48°/52°Light
9

2015 All-Out Fallfest Half Marathon

Clear conditions throughout the day.

2015
clear-day
52°/81°-
8
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