Today's a decent window to get your miles in, but don't get too comfortable with that morning sunshine – things are shifting, and some of our favorite spots are still a mess.
- Your Lungs Will Thank You: Seriously, the air quality is pretty much perfect today with an AQI of 25. Breathe deep, you won't get this every day in the Bay.
- Pollen's Moderate, Not Murderous: It's not going to kill you, but if you're sensitive, you might feel those moderate pollen levels. Keep a tissue handy, or just embrace the snot rocket aesthetic.
- Rain on the Horizon: While it's clear now and a comfortable 13°C, the forecast is pointing to light rain later today and tonight. Those trails are going to get slick, especially on the descents.
- Trail Closures Persist: Some of our favorite spots are still dealing with the aftermath of past storms and ongoing maintenance. You’ll need to do some rerouting.
The Full Rundown
Alright, San Jose, let's talk brass tacks. You woke up to crisp, clear air and a cool 13°C, which is pretty much prime running weather. The AQI is sitting pretty at a glorious 25, meaning your lungs get a vacation from all the usual city grime. Go ahead, hit that deep inhale, it’s good stuff.
However, don't just blindly follow that sunshine. The good vibes are, apparently, temporary. We're looking at a shift to light rain later today and into the evening, with a decent chance of precipitation. That means those beautiful dirt trails can go from grippy to treacherous real fast. If you're planning a longer run, especially anywhere with exposed rock or roots, consider pushing it up to earlier in the day or sticking to pavement. Nobody wants a twisted ankle because they ignored a little drizzle.
Pollen Report
| Pollen Level | Dominant Types | Impact |
|---|---|---|
| Moderate | Various | Seasonal allergy sufferers may experience symptoms. |
Yeah, "moderate" pollen. For some of us, that's just background noise. For others, it's a full-blown attack on their sinuses. You know your body. If you typically react, maybe an antihistamine before you head out is a good idea. Or, again, just embrace the snot. It builds character.
Local Trail Hazards & Closures
Here's where it gets annoying. While the air is clean, some of our go-to routes are still having issues. Alum Rock Park, bless its historic heart, is currently a bit of a labyrinth. The Penitencia Creek Trail is closed at the Trestle Bridge portion, so you'll have to use the park road for a detour. And don't even think about the Mineral Springs Trail; it's shut down due to erosion. Those 2023 atmospheric river events just keep on giving, apparently, with temporary metered lights still on Penitencia Creek Road to manage traffic around damaged sections.
Expect potentially slippery surfaces on trails later today if the forecasted light rain arrives. Be extra cautious on downhills and technical sections.
Over in Santa Clara County Parks, the Lower Calaveras Fault Trail at Sierra Vista Open Space Preserve remains closed due to extensive storm damage. And if you usually hit up Anderson Lake County Park, prepare for the long haul; many areas are closed until approximately 2032 for the Anderson Dam Seismic Retrofit Project. That's not a typo. Two thousand thirty-two.
Always check the official San Jose Parks & Rec site or Santa Clara County Parks website before you head out. Conditions can change faster than a politician's promise.
While there's ongoing levee repair work on the Guadalupe River Trail south of Tasman Drive, those are typically weekday closures. Since it's Saturday, you should be clear, but still, keep an eye out for any unexpected machinery or signage. Safety first, people.
So, get out there, enjoy the cool, clear morning. But be smart, respect the closures, and maybe don't plan on summiting Mount Hamilton if you're not keen on a damp, muddy return.
Data grounded with Google Search from April 11, 2026.