The coming holiday weekend is taking shape as a prototype for summer: Blue skies, highs in the 70s at Tahoe and across the Sierra Nevada, dozens of full lakes and hundreds of campgrounds opening this week.

In the Sierra, Cascade and Siskiyou ranges, the snowline is roughly 7,000 to 8,000 feet, depending on slope exposure. Above that, the high country is still loaded. At Lassen Volcanic National Park, for instance, snowplow crews reported a snow depth of 14 feet on the Lassen Park Highway at an elevation of 8,500 feet near the foot of 10,457-foot Lassen Peak.

Come the weekend, campsite availability at gorgeous lakeside sites will be the best in five years. The Forest Service is opening hundreds of sites this week. It will get even better from mid-June into July as the snow melts in the high country.

For camping, a phenomenon developed this past winter when roughly 15,000 Californians gamed the reservation system and locked up the sites at a relative handful of marquee campgrounds for weekends and at the most popular areas. This includes Point Reyes National Seashore, Yosemite National Park, the coast at Monterey Bay and Big Sur, and the Steep Ravine Cabins on the Marin Coast.

That still leaves roughly 1,200 campgrounds, plus hundreds of private resorts with cabins and campsites, to pick from for the coming summer. It starts Friday.

Bay Area

All the marquee campgrounds are booked full. They include Point Reyes National Seashore, Del Valle Regional Park, Anthony Chabot Regional Park, Big Basin Redwoods and Half Moon Bay State Beach.

Campsites available: Mount Diablo, Brannan Island State Recreation Area, Little Basin. First-come, first-served: Castle Rock; Pantoll and Bootjack at Mount Tamalpais.

Day trips: Party-boat skippers at San Francisco’s Fisherman’s Wharf again will offer the “just-show-up” one-hour bay boat tours, on which for $15, you get a ride along the San Francisco shore, out to Alcatraz and around the Golden Gate Bridge. Boats (they rotate): Lovely Martha, Chucky’s Pride, Wacky Jacky, Silver Fox, Bass-Tub, Happy Days, Amigo.

Tahoe

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The weather looks stellar for the weekend. It will look like another world compared with last weekend, when heavy snow flurries were the trigger point for a traffic mess on Interstate 80 at Donner Summit for people who were not ready for them. Despite that storm, snowmelt has been rapid and many recreation sites are opening this week. In the wilderness, the best projection is that Desolation and Granite Chief will not be accessible until mid- to late June.

Campgrounds: Bayview Campground, Fallen Leaf Camp, Kaspian, Meeks Bay, William Kent, Nevada Beach all opened last weekend. Luther Pass opened Wednesday. Note: Blackwood Canyon Campground will not be open this weekend; it opens Tuesday.

State parks: At D.L. Bliss near Emerald Bay East, Ridge Campground (sites 91-112) will open Thursday and be first-come, first-served through June 8. There’s an opportunity right there. Beach Camp (sites 141-165) and West Ridge (113-130) switch to reservations Thursday for Memorial Day weekend and beyond. Elsewhere, as of Wednesday, Sugar Point and Donner Memorial had campsites available for at least one day or more for the weekend.

Lake levels: The water elevation at Lake Tahoe 6,223.78 feet (natural rim at 6,223, full pool is 6,225); Donner Lake (94 percent full), Independence Lake (100), road is snow-covered, Stampede (47).

Crystal Basin

The Crystal Basin in Eldorado National Forest is the front country to Tahoe. It spans from the western slopes above Placerville to the granite rim of Desolation Wilderness, which looks like crystal when coated with ice and snow. The road in from U.S. 50 is paved, clear of snow, with access to the bigger lakes, and most all of the campgrounds opened by the past week. Wrights Lake is snowed in and Sunset Loop at Union Valley Reservoir is closed to prevent disruption to an active bald eagle nest.

Lake levels: Union Valley (99 percent full), Loon (96), Ice House (93).

Info: Pacific Ranger District, (530) 644-2349, www.fs.usda.gov/eldorado.

Bowman Lakes

The Bowman Lakes Recreation Area is located off Highway 20, east of Grass Valley (north of Interstate 80 near Yuba Gap), and at peak summer, provides access to more than a dozen lakes by 4-wheel-drive and trails, and the primary trailheads are crowded. The snow holds longer on dirt roads (compared with asphalt) and there is no access to the primary destinations, Carr and Lindsey Lakes and trailhead, and Grouse Ridge. No campgrounds are expected to be open.

Lake levels: Fuller, Lindsey, Carr, Milk, Island, Faucheries and most others in region at 100 percent or higher; Bowman (95 percent full), still rising.

Info: Yuba River Ranger District South, (530) 265-4531, www.fs.usda.gov/tahoe.

Gold Lakes

The Gold Lakes are formally known as the Lakes Basin Recreation Area. The area bridges Plumas and Tahoe national forests, is edged by the Sierra Buttes and includes some of the prettiest small lakes anywhere.

Gold Lake Road, Bassetts to Graeagle, opened two weeks ago. Most of the campgrounds opened last week on the Plumas side, including at Goose Lake and Haven Lake, and on the Tahoe side, at Sardine Lake and Packer Lake. The road above Packer Lake has snow, and the trail to the Sierra Buttes is still buried; probably three weeks off for access. The mountain-bike shuttle from Downieville up to Packsaddle for the ride down Butcher Ranch to the Yuba River at Downieville is also a week or two away from clearing.

Lake levels: Sardine, Packer, Gold, Salmon, Haven, Goose, Long, many others, all 100 percent full.

Info: Yuba River Ranger District North, (530) 288-3231, www.fs.usda.gov/tahoe; Beckwourth Ranger District, (530) 836-2575. www.fs.usda.gov/plumas.

Lassen

At Lassen Volcanic National Park, snow is 10 to 15 feet along the Lassen Park Highway (Highway 89) from the Bumpass Trailhead past Helen Lake to the pass below Lassen Peak. That will keep most of the park closed this weekend. From the entrance near Old Station, the road is open to Manzanita Lake, Loomis Museum, Chaos Crags and Devastated Area (closed to Summit Lake). At the southwest entrance, the road is open to the visitor center; in the backcountry, the road is open to Butte Lake; road is plowed to Warner Valley but still closed; road is closed to Juniper Lake. As of Wednesday, all seven campgrounds were closed; Manzanita Lake Campground, which had been open and then closed by snow last weekend, is expected to open Friday without potable water.

State parks

The following had campsites available for stays of one to three days:

Big Sur: Andrew Molera, first-come, first-served.

Sierra Nevada: Calaveras Big Trees, Grover Hot Springs, Plumas-Eureka.

Wine Country: Clear Lake (including cabins).

Redwood Empire: Del Norte Redwoods, Grizzly Creek Redwoods, Humboldt Redwoods, Patrick’s Point, Richardson Grove, Standish-Hickey.

Central Valley and foothills: Colusa-Sacramento River, Folsom Lake, Lake Oroville, Columbia, Malakoff Diggins, San Luis Reservoir, Turlock Lake, Woodson Bridge. First-come, first-served:

North State: Castle Crags, McArthur-Burney Falls cabins; Ahjumawi Lava Springs, first-come, first-served.

Recreation lakes

The big ones: Whiskeytown Lake (98 percent full), Oroville (95), Bullards Bar (95), Pardee (93), Shasta (92), Clear (6.9 feet at the Rumsey Gauge at Lakeport; full at 7.56); Folsom (86), Almanor (80), Don Pedro (74), Camanche (66).

Others of note: Antelope (102 percent full and spilling), Bucks (100), Stumpy Meadows (100), Stony Gorge (100), French (100), Jenkinson/Sly Park (100), Siskiyou (100), East Park (100), Rollins (100), Hennessey (100), Independence (100), Pinecrest (97), Lewiston (96), Mendocino (70).

Yosemite

If you do not have reservations for lodging or camping, do not go to Yosemite for an overnight trip. Some hotels outside the park have reservations available. In Yosemite Valley, Upper Pines, Lower Pines, North Pines and Camp 4 (first-come, first-served, crowded “combat camping”) are open. For campgrounds on the Tioga Road corridor, the hope is they will open by Fourth of July. Tioga Road (and Glacier Point Road) opened last week, but was closed by last weekend’s snow; expected to reopen for the weekend.

Info: Yosemite National Park, (209) 372-0200, www.nps.gov/yose; visitor information, lodging,www.YosemiteExperience.com.

Note: State and federal websites use standing platforms and often do not update news or conditions on a schedule. At Yosemite, for instance, for road updates, phone (209) 372-0200, option 1, ext. 1.