It's race day!

Grasslands Trail Run Marathon

Decatur, TX, USA • March 21, 2026

Race Day Weather

56°

92° high

Breezy

Dry

Warm conditions, stay hydrated

Runners will face a temperature rise from 57°F at the start to a warm 89°F by the finish. With a gentle breeze peaking at 7 mph from the S, conditions will remain dry and pleasant. Runners should prioritize hydration and consider adjusting their pace as temperatures climb, particularly in the later miles.

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Pace Calculator

Distance: 26.2mi

Target Finish Time

0:00:00

HH:MM:SS

Pace

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Weather Adj.

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Common Goals:

The Grasslands Trail Run is held in the Lyndon B. Johnson National Grasslands, more than 20,000 acres managed by the U.S. Forest Service and situated north of Fort Worth. The trails loop among rolling hills and through a mixture of pine and oak grove forests, open fields, and livestock. Run the 100-Mile, 50-Mile, Marathon, Half marathon (Saturday Start) or 15K (Sunday Start) and enjoy the beauty of the Grasslands while sharing the trails with horses and running past cows—don’t let the cows out! Source

Course Map

FAQ

When is the 2026 Grasslands Trail Run Marathon?

The 2026 Grasslands Trail Run Marathon will be held on Saturday March 21, 2026.

Is the Grasslands Trail Run Marathon a Boston Marathon Qualifier?

No, the Grasslands Trail Run Marathon is NOT a Boston Marathon qualifier.

What will the weather be like for the 2026 Grasslands Trail Run Marathon?

The forecast calls for a high of 93°F and a low of 56°F with a 0% chance of rain. Check our detailed hourly forecast above for the best marathon race plan.

Historical Weather

Based on 23 years of data

Avg Temp

63°F

L:48° H:63°

RunScore

Conditions

Rain Freq

22%

5 of 23 yrs

Wind10mph

Dew42°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

Year	Low / High	Rain	Dew Point
2025 Grasslands Trail Run Marathon Partly cloudy throughout the day. 2025	53°/62°	-	30°
2024 Grasslands Trail Run Marathon Partly cloudy throughout the day with rain. 2024	52°/57°	Light	52°
2023 Grasslands Trail Run Marathon Clear conditions throughout the day. 2023	38°/52°	-	23°
2022 Grasslands Trail Run Marathon Clear conditions throughout the day. 2022	43°/71°	-	26°
2021 Grasslands Trail Run Marathon Clear conditions throughout the day. 2021	43°/64°	-	35°
2019 Grasslands Trail Run Marathon Clear conditions throughout the day. 2019	38°/56°	-	21°
2018 Grasslands Trail Run Marathon Clear conditions throughout the day. 2018	53°/69°	-	36°
2017 Grasslands Trail Run Marathon Clearing in the afternoon. 2017	60°/81°	-	61°
2016 Grasslands Trail Run Marathon Clear conditions throughout the day. 2016	37°/56°	-	28°
2015 Grasslands Trail Run Marathon Partly cloudy throughout the day with rain. 2015	50°/58°	-	50°
2014 Grasslands Trail Run Marathon Cloudy skies throughout the day. 2014	53°/59°	-	36°
2013 Grasslands Trail Run Marathon Cloudy skies throughout the day with rain. 2013	41°/49°	Light	45°
2012 Grasslands Trail Run Marathon Clear conditions throughout the day. 2012	51°/72°	-	48°
2011 Grasslands Trail Run Marathon Clear conditions throughout the day. 2011	63°/82°	-	59°
2010 Grasslands Trail Run Marathon Cloudy skies throughout the day with rain or snow clearing later. 2010	32°/35°	Light	30°
2009 Grasslands Trail Run Marathon Clear conditions throughout the day. 2009	56°/71°	-	49°
2008 Grasslands Trail Run Marathon Clear conditions throughout the day. 2008	42°/71°	-	32°
2007 Grasslands Trail Run Marathon Partly cloudy throughout the day. 2007	61°/75°	-	58°
2006 Grasslands Trail Run Marathon Clear conditions throughout the day. 2006	37°/61°	-	33°
2005 Grasslands Trail Run Marathon Partly cloudy throughout the day with a chance of rain throughout the day. 2005	46°/49°	Moderate	46°
2004 Grasslands Trail Run Marathon Partly cloudy throughout the day with late afternoon rain. 2004	69°/81°	-	66°
2003 Grasslands Trail Run Marathon Partly cloudy throughout the day with rain. 2003	47°/58°	Light	47°
2001 Grasslands Trail Run Marathon Partly cloudy throughout the day with early morning rain. 2001	46°/70°	-	54°