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Courtney Dauwalter runs during the Desert Solstice 24-Hour Track Invitational in Phoenix, AZ. Photo Howie Stern

What’s Up in Ultra This Weekend — December 20, 2025

Drew Dinan 12/17/2025
Drew Dinan 12/17/2025
7.9K

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The weekend before Christmas slows down with only 18 events on the UltraRunning Magazine race calendar. In this week’s What’s Up in Ultra, we highlight races in California, Arizona and Massachusetts. If you’re a race director and would like your event to be featured in the calendar, register here.

Featured: Woodside Ramble (Woodside, CA)

The 14th annual Woodside Ramble is a classic Northern California ultramarathon set on the beautiful trails of Huddart and Wunderlich Parks on the San Francisco peninsula. The 50k event kicks off at 8 a.m. Saturday and takes runners along scenic fire roads and singletrack trails with long stretches under towering second and third-generation redwoods. Participants have 9 hours to complete the runnable yet rolling course, which features approximately 5,400 feet of elevation gain and loss. Read more about the Woodside Ramble here.

Other West Events:

Pacific

  • Paramount Ranch Trail Runs (Calabasas, CA)
  • Dirty December Poker Run (San Diego, CA)
  • Hawaii Kai Ultra Run – Kalama Valley (Honolulu, HI)
  • Winter Solstice Vertical Challenge (Quilcene, WA)

Mountain

  • No events

Featured: No events this weekend.

Featured: Desert Solstice (Phoenix, AZ)

The Desert Solstice Track Invitational takes place December 20-21 at the Central High School track in Phoenix, Arizona. The elite-level 24-hour/100-mile event is designed for setting records and provides an ideal qualifying setting for runners looking to make the USATF 24-Hour National Team. Since its debut in 2010, the meet has produced more than 100 national records and 15 world records, and this year’s field is once again stacked with long-distance speedsters aiming to add their names to the record books. The event gets underway at 8 a.m. on Saturday, and you can follow all the action on the Aravaipa Live stream. Learn more about the Desert Solstice Track Invitational here.

Other South Events:

Southwest

  • Cave Creek Thriller (Cave Creek, AZ)
  • Texas Double (Dallas, TX)
  • Naughty Hog (Valley View, TX)

Southeast

  • Ancient Oaks (Titusville, FL)
  • Lake Wales 12hr / 6hr (Lake Wales, FL)
  • Lookout Mountain (Lookout Mountain, GA)
  • Longest Night (Greenville, SC)
  • Charleston Itty Bitty 50 (Mount Pleasant, SC)
  • WV Winter Solstice Endurance Run (Helvetia, WV)

Featured: Seth’s Fat Ass (Springfield, MA)

First run in 2010, Seth’s Fat Ass 50k is a low-key ultramarathon held at Forest Park in Springfield, Massachusetts. Runners have 7 hours to complete 10 loops of the Harrier’s Snow Storm Classic 5k course to reach the full 50k distance, though true to fat ass tradition, participants are free to run as far as they’d like. On course, runners can expect rolling hills with 1,250 feet of combined elevation gain and loss, and must be prepared for chilly winter weather conditions. One aid station is available at the start and finish of each loop, and in past years, many runners have also used their cars for gear swaps and nutrition drops. Read more about Seth’s Fat Ass 50k here.

Other Northeast Events:
  • Blackbeard’s Bounty Endurance Race (Pennsburg, PA)

No events this weekend.

Email corys@ultrarunning with questions about adding your event to the UltraRunning Magazine calendar.

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Drew Dinan

Drew Dinan traded the tropics of the Florida Keys for the trails of Bend, OR. Once living the Jimmy Buffett lifestyle, working on fishing boats and owning only a single pair of flip flops, he now has way too many running shoes in his closet and never hears the end of it from his loving wife. He is on a constant quest to find the best happy hours, likes to complain when it’s cold outside, and one day hopes to travel the country writing reviews on chicken wings.

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