All-Out Fallfest Half Marathon

Westminster, CO, USA · September 19, 2026

57°·79° high·Light·Dry

Weather

Race Day Weather

57°at start

82° high

Light

Dry

Warming day, light winds

Runners will face a temperature rise from 53°F at the start to a warm 81°F by the finish. With light winds from the S, maintaining hydration will be key, especially as humidity stays low at 32%. Adjusting pace to start conservatively will help manage the increasing heat.

Race day forecast available in 118 days

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Distance: 13.1mi

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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

Course Map

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

The forecast calls for a high of 80°F and a low of 51°F with a 4% chance of rain.

Historical Weather

Based on 9 years of data

Avg Temp

78°F

L:54° H:78°

RunScore

Conditions

Rain Freq

11%

1 of 9 yrs

Wind5mph

Dew34°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°/74°	-	45°
2024 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2024	59°/87°	-	38°
2022 All-Out Fallfest Half Marathon Partly cloudy throughout the day with afternoon rain. 2022	55°/76°	-	45°
2021 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2021	51°/88°	-	38°
2020 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2020	58°/83°	-	39°
2019 All-Out Fallfest Half Marathon Becoming cloudy in the afternoon. 2019	56°/75°	-	29°
2018 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2018	53°/85°	-	31°
2017 All-Out Fallfest Half Marathon Partly cloudy throughout the day with rain. 2017	48°/52°	Light	42°
2015 All-Out Fallfest Half Marathon Clear conditions throughout the day. 2015	52°/81°	-	44°

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