All-Out Fallfest Half Marathon

Westminster, CO, USA · September 19, 2026

61°·71° high·Light·Dry

Weather

Race Day Weather

61°at start

75° high

Light

Dry

Comfortable temps, warming through the race

Starting at 61°F, heat will be a factor from the gun — go out conservative and stay on top of hydration. Temperatures rising to 75°F through the course will gradually increase perceived effort in the second half. Light winds shouldn't be a major factor for pacing.

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1 PM

Pre-raceRace windowPost-race

Pace Calculator

Distance: 13.1mi

Target Finish Time

0:00:00

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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.

Website

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 77°F and a low of 57°F with a 28% chance of rain.

Historical Weather

Based on 10 years of data

Avg Temp

70°F

L:50° H:70°

RunScore

Conditions

Rain Freq

0 of 10 yrs

Wind4mph

Dew39°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

Year	Low / High	Rain	Dew Point
2025 All-Out Fallfest Half Marathon Clear conditions throughout the day with rain. 2025	55°/72°	-	45°
2024 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2024	55°/74°	-	39°
2023 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2023	46°/65°	-	40°
2022 All-Out Fallfest Half Marathon Partly cloudy throughout the day with afternoon rain. 2022	50°/70°	-	46°
2021 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2021	46°/73°	-	40°
2020 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2020	52°/76°	-	43°
2019 All-Out Fallfest Half Marathon Becoming cloudy in the afternoon. 2019	53°/69°	-	30°
2018 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2018	47°/76°	-	37°
2017 All-Out Fallfest Half Marathon Partly cloudy throughout the day with rain. 2017	47°/52°	-	41°
2015 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2015	49°/70°	-	44°

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