The North Cascades Highway, State Route 20, is closed by snow for roughly five months a year, and that single fact should shape your whole plan. WSDOT gates a 37-mile section between the Ross Dam trailhead at milepost 134 and the Silver Star gate at milepost 171, covering Rainy Pass at 4,862 feet (1,482 m) and Washington Pass at about 5,475 feet (1,669 m). Recent reopening dates have landed between mid-April and mid-May, closures between early November and early December. Ride it open, it is arguably the best road in Washington. Ride at it closed, you get a gate and a long backtrack.
Why riders rate it
SR 20 is the northernmost highway crossing of the Cascades and it goes through terrain that no other paved road in the lower 48 quite matches — glaciated peaks straight off the shoulder, granite spires at Washington Pass, and a hydroelectric chain of lakes on the western approach that runs an unreal turquoise from glacial silt. The National Park Service describes roughly 30 miles of it as crossing North Cascades National Park and suggests allowing at least an hour for that stretch alone.
The honest limitation: this is a flowing two-lane highway, not a technical mountain road. There is one properly memorable set of curves, on the eastern descent from Washington Pass, and long stretches either side that are fast, open and scenic rather than demanding. Riders who measure roads by corner count leave underwhelmed. Riders who came for scale do not.
Route at a glance
| Road | State Route 20, Burlington and Sedro-Woolley in the west to Winthrop and Twisp in the east |
| Seasonal gate | MP 134 (Ross Dam trailhead) to MP 171 (Silver Star gate), 37 mi (60 km) |
| Later winter gates | Newhalem MP 120 west, Early Winters MP 178 east |
| Summits | Rainy Pass 4,862 ft (1,482 m), Washington Pass about 5,475 ft (1,669 m) |
| Through the national park | About 30 mi (48 km), allow an hour plus stops |
| Typical open season | Mid-April to mid-May until early November to early December |
| Tolls or fees | None to drive through; no entrance station on SR 20 |
Open the route in Google Maps — Marblemount to Diablo Lake to Washington Pass to Winthrop, ready to send to your navigation before the signal disappears.
The closure, verified
This is the detail worth getting right, so here is the sourcing. WSDOT's news release announcing the 2025 winter closure names the gates precisely: Rainy Pass and Washington Pass close between the Ross Dam trailhead at milepost 134 and the Silver Star gate at milepost 171, and as the season deepens the closure points typically move down to the Newhalem gate at milepost 120 on the west side and the Early Winters gate at milepost 178 on the east. WSDOT keeps a full history of mountain pass opening and closing dates going back to 1972.
Recent years, straight off that table: opened April 22 and closed Dec. 4 in 2025; opened April 19, closed Nov. 18 in 2024; opened May 11, closed Nov. 30 in 2023; opened May 10, closed Nov. 3 in 2022. Outliers exist in both directions — the earliest recorded seasonal closure was Oct. 17, 2007, the latest Jan. 3, 1990. And 2026 was an unusually messy year: a partial reopening on April 30 followed by emergency repair work, with WSDOT reporting the highway fully reopened June 14.
The National Park Service summarises the pattern the same way, that snow and avalanche hazards usually close the highway in late November or early December and it usually reopens in April or early May, conditions depending. Their road conditions page is worth a look for the side roads too. Checked August 2026 — but check it again yourself before you go, because none of these dates are a schedule. WSDOT closes on conditions, sometimes with a day of notice, and the real-time mountain pass reports are the live version.
West side, Skagit valley to Diablo Lake
From Burlington the highway follows the Skagit River east through farmland, then Concrete and Marblemount, and the character changes at Newhalem where the walls close in. The North Cascades Visitor Center sits at milepost 119.9, Newhalem at 120.5, and Gorge Creek Falls at 123.4. The set-piece is Diablo Lake Overlook at milepost 131.7, a big pullout looking down on water that photographs as if the saturation slider has been abused. It has not; the colour is rock flour suspended in glacial meltwater.
This stretch is also the northern arc of the Cascade Loop, a 440-mile National Scenic Byway that ties SR 20 to the Methow Valley, Lake Chelan, Leavenworth and Stevens Pass before returning to Puget Sound. Most riders who come from out of state do the loop over three or four days rather than SR 20 as an out-and-back, which solves the problem of riding the same pass twice.
Rainy Pass, Washington Pass and the descent
Past Ross Lake the road climbs to Rainy Pass at 4,862 feet, then a short run to Washington Pass. The overlook there, a short spur off the highway, looks straight down at the hairpin you are about to ride with Liberty Bell Mountain standing over it — it is the picture everyone associates with this road, and it is worth the two-minute detour. The eastern descent toward Early Winters is the best sequence of corners on the route: open, well-sighted, downhill sweepers that reward a bike with decent brakes and punish target fixation on the scenery.
From there it opens into the Methow Valley, drier and warmer, with Mazama and then Winthrop as the obvious stop. The temperature change across the pass is real — the west side is coastal rainforest, the east side is closer to high desert, and riders regularly shed a layer within twenty miles.
Fuel, weather and traffic
Fuel. There is nothing between Marblemount and Mazama, and that is the longest gap on the route by a wide margin. Fill in Marblemount going east or Winthrop going west and the problem disappears. Ignore it on a bike with a small tank and you will spend the descent doing arithmetic.
Weather. Snow can fall at Washington Pass in any month, and shoulder-season riders find wet leaves, sand left from winter treatment, and rockfall debris on the inside of corners. Early in the season, right after opening, the road surface is usually at its worst.
Traffic. Summer weekends bring RVs on a road with limited passing, and law enforcement works the Methow Valley end. There is no gain in hurrying the straight sections; the corners are where the road is worth anything anyway.
Gear notes for this route
Cell coverage across the middle of this highway ranges from patchy to absent, which is the practical argument for having the route stored locally rather than streamed. Setting it up as an offline map on a bar-mounted motorcycle riding system means the turn to the Washington Pass overlook is still on screen in a dead zone, and our route planning guide covers building a day like this with fuel stops placed against the Marblemount-to-Mazama gap rather than against a distance you guessed. A JADO S6 riding system handles navigation and recording on one screen, which is useful on a road where the interesting evidence is usually scenery rather than incident.
The elevation and temperature swing across the passes is the other thing worth preparing for. Riders leaving a warm Skagit valley morning arrive at 5,475 feet noticeably colder, and pressure follows temperature — the numbers behind that are in our tire pressure guide, with the mechanism explained in why pressure drops in cold weather. Given the shoulder-season grit on that eastern descent, a TPMS sensor set giving live readings beats checking at a gas station two hours earlier.
FAQ
When does the North Cascades Highway open each year?
Usually between mid-April and mid-May. WSDOT records show April 22 in 2025, April 19 in 2024, May 11 in 2023 and May 10 in 2022. In 2026 a partial reopening came April 30 with full reopening on June 14 after emergency repairs, so treat any date as provisional until WSDOT confirms it.
When does it close for winter?
Typically early November to early December. It closed Dec. 4 in 2025, Nov. 18 in 2024 and Nov. 30 in 2023. The earliest recorded closure was Oct. 17, 2007, the latest Jan. 3, 1990.
Which part of SR 20 actually closes?
The gated section runs from the Ross Dam trailhead at milepost 134 to the Silver Star gate at milepost 171. Later in winter the gates move down to Newhalem at milepost 120 and Early Winters at milepost 178. West of Newhalem and east of Winthrop the highway stays open year-round.
How long does the ride take?
Most riders treat Seattle to Winthrop over the pass as a full day one way, or a long weekend as a loop returning via Stevens Pass or Blewett Pass. The park section alone wants an hour before stops, and you will stop.
Is there fuel over the pass?
Not between Marblemount and Mazama. That is the gap to plan around; everything else on the route is comfortably spaced.
