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Annadel Half Marathon

Name: Annadel Half Marathon
Start: 2026-04-18
End: 2026-04-18
Location: Santa Rosa

Santa Rosa, California, United States

calendar_today 18 Apr, 2026

directions_run Running

language Official Website

sell $60.83 – $119.68

About the Event

Celebrate 15 years of trail running and stewardship at the Annadel Half Marathon, 10K, and 5K in Santa Rosa on Saturday, April 18, 2026.

This premier non-profit fundraising event draws runners of all levels to the breathtaking trails of Trione-Annadel State Park, supporting its preservation and beauty.

Your registration directly contributes to the park, with a portion of proceeds donated to ensure this natural treasure remains pristine for future generations to enjoy.

Honoring Earth Day with a low-waste, cup-free approach, the event embodies the principle of "protect the place you race" through sustainable practices.

With a generous 4-hour cutoff for the half marathon and welcoming 10K and 5K options, the races are perfectly designed for both seasoned trail runners and enthusiastic newcomers.

Secure your spot before the price increase to guarantee your entry in one of Sonoma County's most beloved and impactful running traditions.

Lace up your trail shoes for a morning where every mile run is a mile given back, combining the challenge of rugged terrain with the deep satisfaction of environmental philanthropy.

Join the community in Annadel for a race that proves the best finish lines are those that leave the park—and the world—a little better than we found it.

Races Offered

10K

Apr 18, 2026

straighten

Distance — 10km

terrain

Type — Running

timer

09:00

sell

$71.53

5K

Apr 18, 2026

straighten

Distance — 5km

terrain

Type — Running

timer

09:00

sell

$60.83

Half Marathon

Apr 18, 2026

straighten

Distance — 21km

terrain

Type — Running

timer

09:00

sell

$119.68

Weather History

These values represent the 3-year monthly averages for April in Santa Rosa.

thermostat Temperature

7.6° / 19.9°

wb_sunny Feels like

5.6° / 17.4°

light_mode Avg sunshine hours

11h 11m

water_drop Avg rainfall

0.6 mm

ac_unit Avg snowfall

—

air Avg wind speed

7.8 km/h (Light breeze)

opacity Sweat loss rate

Low

terrain Course conditions

Firm and slightly soft

sunny Max UV Index

Moderate (5.0)

humidity_mid Humidity

73.0%

wb_twilight Sunrise

06:33

nightlight Sunset

19:47

About Santa Rosa

Learn more about the host city, Santa Rosa.

Santa Rosa is the largest city in Sonoma County, California, and fifth largest in the San Francisco Bay Area. The city is a jumping off point for visiting the wine country of Sonoma County and the Napa Valley, or driving out to the beautiful coastal and parks throughout the Sonoma County.