When is the Lake Sonoma 100 Mile 2027?

The next Lake Sonoma 100 Mile is expected around Saturday, 16 October 2027, based on the dates of past editions. The organizers have not announced the official date yet.

How hilly is the Lake Sonoma 100 Mile?

The course has 7,640 m of climbing and 7,640 m of descent. We rate it mountain. It is a multiple laps course on trail.

What is the weather usually like at the Lake Sonoma 100 Mile?

Around the race date in 2016–2025, the temperature at the 05:00 start averaged 12°C, rising to about 18°C during the race, with 73% humidity. It rained on about 7% of those days.

How do you get a place in the Lake Sonoma 100 Mile?

Entry is first come, first served. The standard entry fee is about $435. Check the official site for the current registration dates.

What is the cut-off time for the Lake Sonoma 100 Mile?

Runners have 36 hours to finish.

161.7 kmTrail🇺🇸 Geyserville, United States

Lake Sonoma 100 Mile

Saturday, 16 October 2027Estimated dateIn 11 months · Start 05:00

Official site Hotels & flights

Lake Sonoma: 3 distances

Distance	Date	Climb	Highest point	Start	Cut-off	Entry
161.7 kmLake Sonoma 100 Mile	16 Oct 2027	7,640 m	—	05:00	36 h	$435
82.9 kmLake Sonoma 50	16 Oct 2027	3,235 m	—	06:30	16 h	$235
43.1 kmLake Sonoma Trail Marathon	16 Oct 2027	1,800 m	—	08:00	11 h	$175

New in 2026: two 50-mile loops of Lake Sonoma singletrack opening with the Pritchett Peaks climb, for over 25,000 ft of climbing in total.

The Lake Sonoma 100 Mile is a trail 162 km ultra in Geyserville, United States, expected around Saturday, 16 October 2027, starting at 05:00. The multiple laps course has 7,640 m of elevation gain (mountain), and the start temperature on race day has averaged 12°C in recent years. Entry is first come, first served, and the standard fee is about $435. The cut-off is 36 hours.

Something out of date? Suggest a correction · Organizer of this race? · Send photos

Facts checked 10 Oct 2026 against aravaiparunning.com.

Elevation gain

7,640 m

Mountain · ↓ 7,640 m

Start altitude

146 m

above sea level, from terrain data

Temp at start

12°C

Peaks around 18°C

Entry fee

≈ $435

Open entry

Finishers

—

typical year

Course

Multiple laps

36h cut-off

Getting thereFly into SMF (Sacramento), about 123 km from the start

Plan your trip to Geyserville

The race date is not confirmed yet. Searches use your own dates, if you add them.

Photo: U.S. Army Corps of Engineers, photographer not specified or · Public domain

Race date not confirmed: don’t book on it yet

Sat, 16 Oct 2027 is our estimate from the race’s usual place in the calendar, not a date the organizer has announced. Confirm the date before you book travel.

Check the date on the official site

Your travel dates (optional): searches use them

ArriveLeave

Hotels near the start lineNo dates set: choose yours once the race date is confirmed · closest to the start firstSee hotels on Booking.com Flights to GeyservilleNo dates setSee flights on Google Flights

Things to do in GeyservilleKlook Mobile data in United StatesAiralo Airport transfer from SMFKiwitaxi Rent a carEconomybookings

Some of these are affiliate links: if you book or buy through them we may earn a commission, at no extra cost to you.

Lake Sonoma 100 Mile course map

A detailed route is not available for this race yet. The marker shows the race location.

Lake Sonoma 100 Mile elevation profile

Mountain: about 7,640 m of climbing and 7,640 m of descent. A detailed profile isn’t available for this race yet.

Lake Sonoma 100 Mile race-day weather

At start

12°C

Peak during race

18°C

Humidity

73%

Chance of rain

Wind

6 km/h

16 October in past years

Historical averages for 16 October ±3 days, 2016–2025, from 05:00 for 5 hours (70 days sampled). Source: Open-Meteo / ERA5.

Lake Sonoma 100 Mile finish times by age group

Top 10 overall, average of the last 1 edition

Men 24:25:22Women 29:38:28

No data yet. We’re collecting age-group results race by race.

Runner reviews

What time could you run here?Adjust your goal time for this course’s hills and typical race-day weather.Race time calculator →

Lake Sonoma 100 Mile: questions and answers

When is the Lake Sonoma 100 Mile 2027?: The next Lake Sonoma 100 Mile is expected around Saturday, 16 October 2027, based on the dates of past editions. The organizers have not announced the official date yet.
How hilly is the Lake Sonoma 100 Mile?: The course has 7,640 m of climbing and 7,640 m of descent. We rate it mountain. It is a multiple laps course on trail.
What is the weather usually like at the Lake Sonoma 100 Mile?: Around the race date in 2016–2025, the temperature at the 05:00 start averaged 12°C, rising to about 18°C during the race, with 73% humidity. It rained on about 7% of those days.
How do you get a place in the Lake Sonoma 100 Mile?: Entry is first come, first served. The standard entry fee is about $435. Check the official site for the current registration dates.
What is the cut-off time for the Lake Sonoma 100 Mile?: Runners have 36 hours to finish.

Guides for this race

Share this race

WhatsApp Telegram Facebook X LinkedIn Email

Organizing this race? Add it to your website

Show your runners the course facts and race-day weather. Paste this code into your site; it displays the badge below and links to this page. It updates automatically when the race details change.

<a href="https://irun42.com/race/lake-sonoma-100" title="Lake Sonoma 100 Mile on iRun42"><img src="https://irun42.com/badge/lake-sonoma-100.svg" width="300" height="120" alt="Lake Sonoma 100 Mile: course, elevation and race-day weather on iRun42" /></a>

Embed this race on your site

A small race facts card for your club or race website: next date, distance, elevation gain, typical start temperature and course records, with a link to this page. It stays up to date on its own.

<iframe src="https://irun42.com/embed/race/lake-sonoma-100" width="100%" height="250" style="border:0;max-width:420px" loading="lazy" title="Lake Sonoma 100 Mile race facts by iRun42.com"></iframe>

Around the same time

All races in October 2027 →

UTMB

More races in United States

All races in United States →