August in California is a month of beautiful extremes. Depending on where you pin your race bib, you might be navigating the foggy, cool coastline of the Pacific, climbing through shaded redwood groves, or braving the intense late-summer heat of the inland valleys. Training for an August race usually means logging your longest miles through the heat of June and July, so when race day finally arrives, you want a course that makes all that hard work feel worth it.
If you are looking for half marathons in California in August, you have a massive selection—49 races across the state, to be exact. Whether this is your first half marathon and you are looking for a gentle, supportive environment, or you are an experienced runner checking off another state on your long-term journey, August offers something for everyone. You will find a mix of flat road courses perfect for finding a steady rhythm and rugged trail runs built for pure adventure. The key to a great late-summer race is knowing what kind of climate and terrain you want to tackle. Let's look at some of the standout options to help you plan your next starting line.
Humboldt Bay Marathon
If you want to escape the late-summer heat and run a fast, flat course, the Humboldt Bay Marathon in Eureka is a fantastic choice. Earning a Runner Favorite score of 75, this road race offers the kind of cool, coastal weather that runners dream about in August. Because it is USATF certified and entirely flat, it is a brilliant option if you are aiming for a specific time goal or just want a smooth, predictable surface for your first 13.1.
The ocean views and supportive local community make the miles fly by. Running along the bay means you get the benefit of sea-level oxygen and gentle breezes, keeping you comfortable even in the middle of summer. When running a flat course like this, the challenge is often holding back early on so you do not burn out your legs. Settle into a comfortable pace, enjoy the coastal scenery, and let the energy of the other runners carry you through to the finish line. It is the perfect blend of a scenic destination race and a highly organized, runner-friendly course.
Hell Of A Half Marathon & 2 Person Relay
Sometimes you sign up for a race because it is easy, and sometimes you sign up because you want a story to tell. The Hell Of A Half Marathon in Exeter is definitely the latter. Rated as a Standout with a score of 70, this flat road course is famous for one major factor: the heat. The organizers lean right into it, promising a challenging, hot morning surrounded by a community of runners who are all in on the shared struggle.
If the idea of running 13.1 miles in the August heat sounds a little intimidating, they also offer a two-person relay option, making it a great way to split the distance with a training partner. It is a race that tests your mental grit just as much as your legs. If you take this on, hydration and electrolyte management in the days leading up to the race are crucial. The finish line camaraderie here is unmatched because everyone knows exactly how hard you worked to get there. It is the kind of race that makes you feel incredibly capable once it is done.
Bear Creek
For runners who prefer dirt under their shoes and a bit of elevation in their legs, the Bear Creek half marathon in Lafayette is a wonderful late-summer challenge. This Standout trail race, scoring a 61, trades flat pavement for rolling, hilly terrain. Trail races often have a completely different vibe than road races—they are usually a bit smaller, deeply supportive, and focused more on the experience of the landscape than the pace on your watch.
Bear Creek is no exception. The hills will certainly ask a lot of your climbing muscles, so you will want to incorporate some incline work into your training plan. If you are transitioning from road to trail for the first time, remember that walking the steep hills—often called power hiking—is not just acceptable, it is a smart strategy used by the pros. The reward for the effort is a beautiful, nature-immersed run away from traffic and city noise. Pace yourself on the climbs, trust your training, and enjoy the adventure.
SAR Wild Run
Running is always better when it supports a good cause, and the SAR Wild Run at Shaver Lake does exactly that. This Standout event, scoring a 60, is a fundraiser for the Fresno County Sheriff’s Search & Rescue team. It is a fantastic excuse to escape the valley heat and head up into the mountains for a flat, scenic trail run.
Finding a flat trail race in the mountains is a bit of a rarity, making this a highly accessible option for runners who want the beauty of nature without the punishing elevation profiles usually found at higher altitudes. It is a deeply community-focused race where you are running alongside the very people who keep the local wilderness safe. Whether you are a seasoned trail runner or a road runner looking to try something new, the SAR Wild Run offers a welcoming, purpose-driven morning in the pines. Just take a moment to appreciate the fresh mountain air and the incredible volunteers supporting you along the way.
Truckee Half Marathon and 5K
If you cannot decide between road and trail, the Truckee Half Marathon gives you a taste of both. Set in the stunning Sierra Nevada, this mixed-terrain race is a Solid Pick with a score of 58. Truckee in August is an outdoor lover's paradise, offering crisp morning air and incredible mountain views.
Because the course mixes different surfaces, it keeps your mind engaged and your legs guessing. You will want to wear a comfortable, versatile running shoe that can handle a bit of everything. Mixed-terrain races are incredibly fun because they break up the monotony of a standard road race while still giving you stretches where you can settle into a steady rhythm. Plus, Truckee is a fantastic town to spend the weekend in, making this a perfect destination race to share with friends or family. It is a great way to turn a single race morning into a full weekend adventure.
Double Dipsea
Steeped in Northern California running history, the Double Dipsea is a bucket-list race for anyone who loves a rugged, historic challenge. Starting at Stinson Beach, you run the world-famous Dipsea Trail to Mill Valley and then turn right around and run it back. This hilly trail race is a Solid Pick, scoring a 54, and is famous for its unique handicapped starting system.
Runners are given head starts based on age and gender, meaning the first person to cross the finish line actually wins the race outright. It is a brilliant equalizer that makes the race thrilling for everyone involved. With massive climbs, countless stairs, and technical descents, this is not a race for a personal best time. Instead, it is about tackling a legendary route, enjoying the sweeping coastal and forest views, and becoming part of a tradition that has been going strong for over five decades. If you sign up, make sure you find some stairs to practice on during your training!
Santa Cruz Trail Run
There is something genuinely magical about running through giant redwoods, and the Santa Cruz Trail Run in Felton delivers that experience in spades. This hilly, mixed-terrain race is a Solid Pick with a score of 53. The course is a dynamic journey that takes you from coiling single-track trails under the massive tree canopy out to wider paths, with ocean breezes rolling in from the nearby coast to keep you cool.
You might even encounter a bit of sand along the way. It is a true adventure run that requires you to stay present and adapt to the changing ground beneath your feet. The hills will challenge you, but the shade of the redwoods and the sheer beauty of the landscape make every step worth it. It is an ideal late-summer race for runners who want to feel completely immersed in California's natural beauty. Leave your pace expectations behind and just enjoy the incredible environment.
How to Choose Your August Race
With 49 half marathons in California in August, narrowing it down comes down to knowing what kind of experience you want to have. If you are running your very first half marathon and want a predictable, comfortable day, look toward the coast. Races like the Humboldt Bay Marathon offer flat roads and cool temperatures, which take a lot of the stress out of race day and let you focus on simply crossing the finish line.
If you are an experienced runner looking to shake up your routine, August is a great time to hit the trails or try a mixed-terrain event like the Truckee Half Marathon. Trail races generally require a bit more time on your feet, so focus on the effort and the scenery rather than your watch.
Finally, be honest with yourself about the heat. If you thrive in warm weather and love a gritty challenge, inland races will test your endurance in the best way possible. But if you prefer to stay cool, stick to the coastal routes or the shaded redwood forests. No matter which starting line you choose, remember that the goal is to enjoy the journey, celebrate your training, and find your next great adventure. Explore all California half marathons to see the full list and find the perfect fit for your late-summer run.