If you’re thinking about hitting the pavement or trails today, think again – it’s a cooker out there, and some of your favorite spots are actually closed.
- Scorching Heat Advisory: San Diego is under an Extreme Heat Watch, with temperatures expected to be 5-10 degrees above average. Inland valleys and mountains are under a heat advisory through 10 AM, after which the heat becomes more widespread, impacting coastal areas through Friday night. Expect highs around 91°F (33°C), which is plenty hot to cause problems.
- Closed Trails: Seriously, don't even try. Several popular spots like the San Diego River Gorge Trail and Three Sisters trails are closed for the entire month of August due to extreme heat and a history of heat-related rescues. El Capitan Preserve, Hellhole Canyon, and Mt. Gower Preserve are also shut down. This isn't for fun; it's to keep you from becoming another statistic for our already stretched emergency services.
- Moderate Air Quality: The AQI is sitting at 67 with PM2.5 as the dominant pollutant. Not terrible, but combined with the heat, it's not doing your lungs any favors.
Extreme Heat Warning in Effect! Seriously high temperatures are here, and overnight lows won't bring much relief. This isn't just uncomfortable; it's dangerous. Heat-related illnesses increase significantly during these conditions. Stay out of the sun, drink plenty of fluids, and don't push it.
Alright, San Diego, let's talk turkey. It's August 25th, and Mother Nature is not messing around. We've got an Extreme Heat Watch gripping the county, and your weather app isn't lying when it says 91 degrees Fahrenheit. Throw in some returning monsoonal moisture bringing humidity to the mountains, and you've got a recipe for a seriously miserable, and potentially dangerous, outdoor workout.
Forget about tackling anything strenuous in the inland valleys, mountains, or even along the coast as the day progresses. The National Weather Service isn't just crying wolf; they're talking about temperatures that can cause heat illness. This isn't the day to try and PR your long run or tackle a new segment on Strava.
And for those of you who love to get out to our beautiful backcountry, hear this loud and clear: many of your favorite trails are GONE for the month. The San Diego River Gorge Trail and the Three Sisters trails? Closed. El Capitan Preserve, Hellhole Canyon Preserve, and Mt. Gower Preserve? Also closed through August due to public safety concerns stemming from, you guessed it, extreme heat. These aren't suggestions; these are closures put in place because people keep getting into trouble out there. Don't be that person who needs a helicopter rescue because you thought you were tougher than a 100-degree day.
Your lungs aren't thrilled either. That AQI of 67 means moderate air quality. It's not the apocalypse, but it's an added stressor when your body is already fighting to keep cool.
Here's the pollen breakdown if you absolutely must know, but honestly, the heat is the bigger villain today:
| Pollen Type | Level |
|---|---|
| Overall | Moderate |
Workout Smarter, Not Harder: If you absolutely cannot skip your workout, move it indoors. Hit the gym, find an air-conditioned spin class, or jump in a pool. If you insist on being outside, stick to short, easy walks in the very early morning or late evening, far away from any closed trails, and bring way more water than you think you need. Seriously, hydrate like it's your job, and listen to your body – it's screaming at you to chill out today.
Data grounded with Newsradio 600 KOGO, KESQ, Caltrans, San Diego County Parks and Recreation, and City Times from August 24-25, 2026.