US-395 to Mammoth: Winter Road Conditions and Routes
Compiled October 2026 from SnoCal's Eastern Sierra research (National Park Service and Caltrans road information). Conditions change by the hour, so check the live sources below before you drive.
Checking Caltrans…
Check your route right now: Caltrans QuickMap for chain controls, closures and cameras, Caltrans Road Information (enter 395, 203 and, from the Bay Area, 80), or call 1-800-427-7623.
The short version
There is no winter road across the Sierra between Lake Tahoe and the Tehachapis. Tioga Road (Highway 120 through Yosemite) is usually closed from November through late May or early June, according to the National Park Service, which covers the entire ski season. Sonora Pass (SR-108) and Ebbetts Pass (SR-4) close for winter too. So US-395 is the only realistic corridor to Mammoth and June Mountain, and your navigation app may still try to route you over a closed pass.
Which way you actually drive
| From | Route | What to watch |
|---|---|---|
| Los Angeles / SoCal | North on US-395, roughly 310 miles from LA | The easy direction: no Sierra crossing. Chain controls on US-395 and SR-203 into Mammoth Lakes in storms |
| Bay Area / Sacramento | East on I-80 over Donner Summit, then south on US-395 | Every I-80 chain control and closure applies to your Mammoth trip too |
| Bay Area (alternative) | South through the Central Valley and around the range | Longer, but avoids Donner |
From Northern California, Mammoth is a weekend-minimum trip. And because the usual route crosses Donner, an I-80 closure strands a Mammoth trip as effectively as a Tahoe one. For a Bay Area day trip, look at Tahoe or the Central Sierra instead.
Chain controls on the way
Mammoth traffic hits chain controls on US-395 and on SR-203, the road from 395 into Mammoth Lakes. June Mountain is about 20 miles north of Mammoth on 395. R2 is the common level: chains on passenger cars unless you have all-wheel or four-wheel drive with snow-tread tires on all four wheels, and everyone must carry chains in a control area. See our chain control guide and which chains to buy.
Does flying help?
Only from Southern California. Mammoth Yosemite Airport has semi-private charter service from selected SoCal airports in winter, and Bishop's commercial service is summer-only. From the Bay Area, the realistic option is flying to Reno and driving south on US-395. Details in our Eastern Sierra guide.
Get the drive outlook every Thursday
Our free Weekend Outlook covers the US-395, I-80, US-50 and SR-88 outlook and our call for the weekend.
How many chain control points Caltrans reports on US-395
Caltrans publishes 20 chain control reporting points for this corridor, covering US-395 itself and the SR-203 spur into Mammoth Lakes, all of them inside Mono County, between 6,863 and 8,973 feet. That is the highest band of any road in this guide, and the only one where every reporting point sits near or above the elevation of a Tahoe summit.
Why mile marker directions for US-395 are unreliable
California does not number its highways continuously. Postmiles reset to zero at every county line, and the letter prefixes that appear in official data, R and M and D and T and L, are separate numbering series rather than variants of one another. A postmile on US-395 therefore means nothing on its own: you also need the county and the prefix before it points at a place.
This is why the live status above is filtered to an explicit postmile window inside Mono County rather than sorted by mile marker. Sorting US-395 by raw postmile interleaves counties nonsensically. Any guide that hands you a bare mile number for a chain control point on 395 has skipped the step that makes the number mean anything.
The full Caltrans code list, including every truck-only code, is on our California chain control explainer.
US-395 to Mammoth: frequently asked questions
Is Tioga Pass open to get to Mammoth in winter?
No. The National Park Service says Tioga Road, Highway 120 through Yosemite, is usually closed from November through late May or early June. Use US-395 instead.
What is the best route from the Bay Area to Mammoth in winter?
Usually I-80 over Donner Summit, then south on US-395. The alternative is south through the Central Valley and around. You cannot cross the Sierra between Tahoe and the Tehachapis in winter.
Is there chain control on Highway 395 right now?
The live panel at the top of this page reads the Caltrans chain control feed, which Caltrans publishes once a minute, and it shows the time Caltrans published it. If it cannot reach Caltrans it says so rather than guessing. Check Caltrans QuickMap at quickmap.dot.ca.gov, look up 395 and 203 at roads.dot.ca.gov, or call 1-800-427-7623. Check again right before you leave.
Live chain control data comes from the Caltrans Commercial Wholesale Web Portal and is published by Caltrans once a minute. SnoCal is not affiliated with Caltrans or the National Park Service and the data is provided without warranty. Always confirm conditions with Caltrans before you travel. Related: Mammoth guide · June Mountain · Where to stay at Mammoth.