"With new trail construction, it is important to allow the trail to rest and 'settle in' over the rainy season before it is impacted by foot and bicycle traffic." That line comes from the Midpeninsula Regional Open Space District's Coal Creek Preserve page. It explains why the Meadow Trail has been closed since April 27, 2026, and will stay closed into April 2027. The point is to let the soil compact and harden again before anyone walks or rides on it.
That closure was set months in advance, and it is one kind of rule. Within a few miles of Portola Road, at least three public bodies decide whether a trail is open this winter. Each uses a different kind of trigger. One follows a rain gauge, one makes a call each day, and one works from posted notices. A storm that closes a trail to horses at Windy Hill may leave the same trail open to hikers. The same storm can close a loop at Pearson-Arastradero to everyone, and the Town's own paths may not change at all. The rest of this piece walks through each rulebook.
Three Rulebooks Within a Short Drive
| Who decides | Where | What triggers a closure | Who it affects | Where to check |
|---|---|---|---|---|
| City of Palo Alto | Pearson-Arastradero seasonal trails | A rainfall threshold measured at Foothills Nature Preserve | All users | Palo Alto trail status page, lot bulletin board, (650) 329-2423 |
| Midpen | Windy Hill, Long Ridge, Monte Bello and other Skyline preserves | Actual and forecast weather, decided day to day | Equestrians, and at some preserves bicyclists | Midpen trail conditions page |
| Town of Portola Valley | Town trail and path network | Rainy-season notices posted by the Town | Equestrians on some wilderness trails | Town trail closures page |
Arastradero Runs on a Number
Palo Alto's rule is the only one of the three written as a formula. Under the city's Seasonal Trail Closure Policy for Enid W. Pearson Arastradero Nature Preserve, four trails are seasonal: Bowl Loop, Woodland Star, Woodrat and Wild Rye. They close when rainfall goes over 0.5 inches in 24 hours or 1 inch within seven days. The rain isn't measured at Arastradero. It is measured at the Foothills Nature Preserve weather station, up the hill.
Reopening is harder. The policy requires at least 48 hours without rain, and even then the trails reopen only when they are dry and no user group leaves tracks. A sunny Saturday after a wet Thursday may still find the Bowl Loop roped off. Most of the seasonal trails sit on the western side of the preserve. Wild Rye is the exception, down in the lower area. Every other trail in the preserve stays open all year.
As of the city's latest preserve alerts update, the seasonal trails are open. That page names only Bowl Loop, Woodrat and Wild Rye. The policy itself lists Woodland Star too. The city also posts the rainfall data behind its decisions on its Creek Monitor page. That lets you check the gauge readings yourself before you drive over.
Midpen Decides by the Day, and by Who Is Using the Trail
Midpen sets no rainfall number. Its trail conditions page asks bicyclists and equestrians to stay off dirt trails during rain and after bigger storms, while standing or running water remains. It also says closures can change from day to day without notice, based on actual and forecast weather.
Closer to home, Midpen's closures depend on how you are using the trail. At Windy Hill, four trails can close to equestrians in wet weather, and none of them closes to hikers:
- Betsy Crowder Trail
- Hamms Gulch Trail
- Lost Trail
- Razorback Ridge Trail
All four are currently listed open to equestrians.
Farther up Skyline, the wet-weather list adds bicyclists. At Long Ridge, the Chestnut, Long Ridge and Peters Creek trails may close to both bikes and horses. At Monte Bello, the list covers Skid Road, the stretch of Stevens Creek Nature Trail between Skid Road and Canyon, and the section of White Oak that connects to Skid Road. All of these are open for now. At Thornewood, Midpen posts a warning instead of a closure. It advises against crossing Dennis Martin Creek on the Bridle Trail during high water.
The Town's Own Network Follows a Third Set of Rules
The Town of Portola Valley's trail rules allow horses on every Town trail except the Toyon Trail on Coal Mine Ridge. They also note that some wilderness trails close to horses during the rainy season, with notices posted on the Town website. Bikes are allowed on paved paths and on certain unpaved trails near schools. They are prohibited on wilderness trails, with a 15-mph limit that drops to 5 mph when passing. That usage document was published by the Trails & Paths Committee in 2012. Signs posted on the trails today are the better guide to current rules.
The Town gives no rainfall trigger. It decides by notice, and it can take a while. Last winter the Trails & Paths Committee announced that the Larry Lane Trail Complex reopened to equestrian use on January 26, 2026. The notice said it could be reassessed if rain required. The Town's trail closures page currently lists no closures.
The Closures Rain Has Nothing to Do With
Some of this winter's closures have already been decided, whatever the weather does. They come from construction schedules, aging structures and a summer fire.
- Coal Creek Meadow Trail. It is closed for drainage and trail-tread work into April 2027. Midpen's page gives two end dates, April 5 and April 7. The preserve's other trails remain open.
- Coal Creek's Silicon Valley Vista Point parking. This 25-space pull-out on Skyline Boulevard is owned and run by Caltrans, and it is temporarily closed. Midpen gives no reason or reopening date. The seven-space Upper Alpine roadside lot is still listed for hikers, bicyclists and equestrians coming from Alpine Road.
- Foothills Nature Preserve, western Fern Loop. During a bridge inspection, staff found rotting structural parts in Bridge 4, which has to be fully replaced. The western side of the loop is closed until the replacement is approved, and the closure is expected to last through the 2026/27 winter. The eastern side stays open and still connects to the Costanoan Trail.
- Arastradero's Page Fire burn scar. A fire on Arastradero Road on June 22, 2026, was contained in about half an hour and mapped at 4.1 acres. That area is closed through June 30, 2027. No trails or fire roads are affected. The closure protects a stand of Kellogg's yampah, a native plant, from invasive weeds like yellow star thistle.
The Meadow Trail rule ties these back to the rain. Midpen timed that closure to cover the wet months on purpose. The rainy season that closes other trails for a few days at a time is the same season the new tread needs to settle.
Planning Fall Around the Trails That Stay Open
Midpen's fall program mostly uses routes the wet-weather rules leave open to people on foot. Its Fall 2026 guide says docent activities are free. Only some need reservations, and those open two weeks ahead.
| Date | Program | Details |
|---|---|---|
| Sun., Oct. 25 | Autumnal Beauty Loop, Windy Hill | 8 a.m.–1:30 p.m., 7.5 miles from the Lower Windy Hill Parking Area, up Spring Ridge to the summit and down Hamms Gulch |
| Tue., Nov. 17 | Take a Hike Day dog hike, Windy Hill | 12:30–5 p.m., 7 miles; reservations open Nov. 3 at noon and close Nov. 16 at 2 p.m. |
| Sat., Nov. 21 | Fall & Winter Berries, Windy Hill | Noon–2 p.m., a 2-mile family walk around Sausal Pond |
| Sat., Nov. 28 | French broom removal, Windy Hill/Hawthorns | 9:30 a.m.–1:30 p.m., meets at gate WH10 on Los Trancos Road; registration required |
The Autumnal Beauty Loop comes down Hamms Gulch, one of the four Windy Hill trails that can close to horses after rain. That restriction doesn't apply to a docent-led group on foot.
Up on Skyline, the same guide lists a Full Moonrise from Borel Hill on Russian Ridge on October 26, Trail Trek Thursday on October 29 and Sunset Serenity on November 5. Monte Bello has Full Moon on Black Mountain on October 25 and November 24, and Ferns & Other Ancient Plants on November 28. Long Ridge has a fall docent series too, including Fall Frolic With a View on November 6 and Early Winter Exploration on November 15.
All of these pages are live. Midpen, Palo Alto and the Town can change a trail's status overnight. The three links in the first table are the most reliable check before you head out.
If you're weighing a property near one of these trailheads, the trail access you see on a dry October day may change once the rains start. Dana Rae Stone can walk you through how a property sits relative to these trails across the seasons. Let's talk about your home.
