Calero Trail Run - Winter | San Jose, CA, United States

About the Event

The Calero Trail Run - Winter takes place on December 5th in San Jose, California, United States. This event is hosted within the scenic boundaries of Calero County Park, offering a range of distances from a Kids Run to a challenging 50K for trail runners.
Participants can expect varying terrain conditions as they explore single-track trails, hills, and dirt paths throughout the park. The race begins at 8:00 AM sharp after an initial kids' race starts earlier in the morning at 7:30 AM followed by a trail briefing at 7:45 AM. The setting is ideal for those looking to train under cooler winter conditions while enjoying panoramic views of oak-dotted landscapes.
This event has been part of the local running community's calendar since its inception, providing both casual runners and serious competitors with an opportunity to challenge themselves in one of San Jose’s most picturesque locations. Funds raised from the race support various environmental initiatives within Calero County Park, ensuring that participants contribute positively towards preserving this natural space.
The course at Calero Trail Run - Winter spans across diverse terrains including single-track trails, hills, and dirt paths, all set against a backdrop of oak trees with stunning panoramic vistas. The route is marked clearly to help runners navigate through the challenging terrain effectively.
Registration for the race opens on December 5th from 7:00 AM at Calero County Park’s entrance located off McKean Road in San Jose. Participants can also register online via [https://ultrasignup.com/register.aspx?did=139558](https://ultrasignup.com/register.aspx?did=139558) with fees ranging from $25 for the Kids Run to $115 for the 50K distance. Bib pickup and registration will be conducted at the race site on that day, allowing runners ample time to prepare.
Weather conditions during December in San Jose typically feature firm yet slightly soft trails, ensuring a stable surface underfoot with low UV index levels providing comfortable running temperatures throughout the morning hours until early afternoon.

Kids Run
Start: 07:30:00 • Fee: $25.00

10K
10K • Start: 08:00:00 • Fee: $65.00

These values represent the 3-year monthly averages for December in San Jose.

thermostat Temperature

7.6° / 15.7°

wb_sunny Feels like

5.7° / 14.3°

light_mode Avg sunshine hours

7h 9m

water_drop Avg rainfall

3.7 mm

ac_unit Avg snowfall

—

air Avg wind speed

5.5 km/h (Light breeze)

opacity Sweat loss rate

Low

terrain Course conditions

Firm and slightly soft

sunny Max UV Index

Low (2.0)

humidity_mid Humidity

80.7%

wb_twilight Sunrise

08:14

nightlight Sunset

17:52

About San Jose

Learn more about the host city, San Jose.

Often called "the capital of Silicon Valley", San Jose is the largest city in the Bay Area, 3rd largest in California, and the 12th largest city in the United States, with a population of over 997,000 residents as of 2024. It was named the 6th safest big city in the U.S. in 2015. This clean, sprawling metropolis has sports, beautiful vistas, and ethnic enclaves and bleeds into the greater Bay Area for travelers who want to take their time in Northern California.

Hotels & Places to Stay

Race Results

All-time top performances and historical records for Calero Trail Run - Winter.

Place	Name	Gender	Age	Year	City	Time
🥇	Oliver Kaard	M	24	'25	—	4:06:12
🥈	Jonathon Hazell	M	31	'24	—	4:32:54
🥉	James Dillon	M	41	'25	—	5:29:00
4	Sean Curry	M	56	'24	—	5:46:53
5	Arnau Bajona	M	25	'25	—	5:49:00
6	Matthew McComish	M	25	'24	—	5:52:34
7	Stephen Sims	M	27	'23	—	5:59:56
8	Daniel Olsson	M	33	'25	—	6:03:12
9	Ezher Salihbasic	M	37	'23	—	6:07:12
10	David Astrue	M	29	'24	—	6:07:22

Place	Name	Gender	Age	Year	City	Time
🥇	Angelica Lerro	F	25	'23	—	6:17:21
🥈	Zoe Bell	F	27	'25	—	6:23:11
🥉	Kelly Winter	F	43	'23	—	6:38:41
4	Michelle Brost	F	54	'23	—	6:48:04
5	Olivia Srednicka	F	22	'22	—	6:55:01
6	Ashley King	F	38	'25	—	6:57:52
7	Jaime Danon	F	49	'25	—	7:00:03
8	Katherine Searcy	F	40	'23	—	7:00:07
9	Jeannie Munoz	F	33	'24	—	7:23:23
10	Emily Mongold	F	26	'24	—	7:48:26