San Jose, CA, United States · Thursday, December 31, 2026

Fixed Distance 100 mi

New Years One Day 100 Mi Run

106 days away
161 km Distance
not publishedn/a Climbing
8.1 est Grit · Hardcore

Calculated from 161 km alone — the organiser has not published an elevation profile. Read 8.1 as a floor, not a verdict.

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37.3394° N, 121.8950° W© OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Field size ~8 Tiny. You will run alone for most of it.

DUV results for the 2025 edition (100mi) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, December

Daytime high 13°C
Night low 4°C
Rainfall Showers likely
Daylight 9 h 37 m of light

Regional 2001-2020 average for December — NASA POWER, grid elevation 233 m. Not a forecast.

The Aid Station

Course-specific beta from the community

👟 gear

With trail terrain, choose a shoe with moderate cushioning for optimal performance.

By UltraHub Expert
🥤 nutrition

For 100km+ efforts, prioritize real food at aid stations to prevent palate fatigue.

By UltraHub Expert

Gear for this race

Chosen for 161 km of trail.

  • Trail Running Shoes161 km of trail — cushioning that is still there in the last quarter.
  • Race NutritionPast 161 km the palate quits before the legs do — carry more than one flavour.
  • Hydration VestsFlask capacity for 161 km, without the bounce.
  • Headlamps161 km almost certainly means running into the night.
  • AccessoriesChafe and blisters end more 161 km races than fitness does.

Salomon

Aero Glide 4 Grvl

$159.95 ★★★★★ 4.5

Adidas

Terrex Agravic Speed Ultra

★★★★★ 4.5

Tailwind

Endurance Fuel

All-in-one calorie and electrolyte drink mix. 200 calories per serving.

$25 ★★★★★ 4.8

Salomon

ADV Skin 12

Industry-standard 12L race vest with front flask pockets and minimal bounce.

$180 ★★★★★ 4.8

Petzl

NAO RL

1500-lumen reactive lighting headlamp with 15-hour runtime. Automatic brightness adjustment.

$150 ★★★★★ 4.7

Squirrel's Nut Butter

Anti-Chafe Balm

All-natural anti-chafe balm. Essential for 100+ mile races.

$12 ★★★★★ 4.8
All gear guides →

Course Notes

Each lap is 1.03 miles (USATF certificated No. CA23033TEB) around Cottonwood Lake in Hellyer Park along the asphalt path. The course is relatively flat.

Similar races

Other 100 mi trail ultras, closest in distance first.