Dillon Reservoir Low Water in Fall 2026: Summit County Outlook

"Meaningful recovery will ultimately depend on improved fall moisture and, more importantly, a strong 2026-27 snow accumulation season."

Denver Water supply manager Nathan Elder said that in September about Dillon Reservoir. Swap the lake for a ski run and it could just as easily come from a snowmaker at Arapahoe Basin. Summit County has two countdowns running this October, one for opening day and one for the lake. Both depend on the same storms.

The lake ran out of summer early

The reservoir never really filled this year. Summit Daily reported that Dillon peaked at 80% full, earlier than usual, after a winter of poor snowpack. Denver Water says the Colorado River Basin snowpack peaked March 18 at 58% of normal. Its September 28 update called last winter's peak more than a month early and the lowest in 40 years.

Then came the summer. From April through July, 47,559 acre-feet flowed into Dillon. That's the lowest on record, below the previous record low of 56,695 acre-feet set in 2002, and far below the roughly 160,000 acre-feet of a typical year. August set its own record for the lowest monthly inflow, and September was tracking just as low. At the end of July, Denver Water was drawing about 163 million gallons a day from Dillon to supply Denver and its suburbs.

Here's how the level has moved:

The early-October row comes from Denver Water's reservoir levels page. The page labels its data preliminary, which makes it a snapshot, not a final reading. The last row is the one to watch. In August, Denver Water projected Dillon would bottom out at 50% to 60% before refilling. By September 23 the lake was already close to that range, and the forecast dropped to 45% to 50%. Elder blamed most of the change on record heat: July ranked among the ten hottest on record for Summit County and Dillon Reservoir, and August set a new record. If the lake lands at the low end, it would sit below the 2002–03 drought mark.

What the shoreline looks like this fall

Frisco saw this coming. Back in February, Summit Daily reported that the Frisco Bay Marina public ramp would not open and slips would not be available for 2026. Denver Water's modeling showed the bay bottom could stay exposed all summer. By mid-September, the Town of Frisco's marina page said low water had ended all powerboat and paddle sport rentals for the season. The town's 2026 brochure describes the usual boating season as early June through the end of September. The marina office at 267 Marina Road is now open weekdays from 9 a.m. to 5 p.m. through May 2027 for questions about slips, mooring balls and kayak rack storage. The two new sand volleyball courts beside it never needed the water.

Dillon held on longer. In July, the Town of Dillon posted that crews were lowering gangways, anchoring them to the lakebed and building a path below the seawall to keep up with the falling water, and rentals kept running. On Thursday, October 1, Dillon Marina switched to fall and winter hours, Monday through Friday from 9 a.m. to 3 p.m. Boat rentals and the launch ramp are now closed for the season.

Low water reached past the docks, too. In August, the Denver Post reported that the water taxi had lost its Frisco-side trips, including concert runs from Frisco to the Dillon Amphitheater. Its operator said about 90% of his business was gone, and he kept launching from Dillon. The amphitheater has since wrapped its 2026 summer concert season.

What the lake gave up is history. On August 20, Summit Historical Society volunteer Ken Raggio stood on a pile of rubble that, in a normal year, would sit under about 10 feet of water. The receding shoreline has exposed patches of asphalt from old highways, rusted iron and railroad pieces tied to Dickey, a railroad outpost that has been underwater for decades. Very little of the original town of Dillon is visible, because Denver Water removed its structures before the reservoir filled.

Where October went instead

With the water closed, this month's calendar has moved into town halls, theaters and Main Streets. Several events already point toward winter:

• Today, October 4: Silverthorne's free Pumpkin Fest at Rainbow Park, 11 a.m. to 2 p.m., with a Halloween costume swap.
• October 10: Frisco's free Repair Fair at Slopeside Hall, 10 a.m. to 2 p.m. Ski and snowboard repair consultations sit alongside the other gear-repair stations, a timely tune-up before lifts start turning.
• October 10: Breck Film screens Elevation at 8 p.m., with Anthony Mackie and George Nolfi appearing in person.
• October 11: Wildflower Kids Fest at the Silverthorne Pavilion. That evening, Breck Film and Matchstick Presents show The Way Out at the Riverwalk at 7 p.m., with athlete appearances and a gear giveaway.
• October 14: The Well with Pink Fuzz and Red Cloud Ritual at 10 Mile Music Hall.
• October 16–17: Breck Create's Día de los Muertos + Latin Festival at the Arts District Campus, with a candlelight vigil, a Latin market, cultural performances and a dance night.
• October 23: The Shining at the Riverwalk Center, 7:30 p.m., part of Breck Create's $5 film series.
• October 31: Trick-or-Treat on Main Street in Frisco, 5 to 7 p.m., plus a 5 p.m. Halloween dog parade and free train rides.

New stops have opened in town, too. Nordstrom Rack opened Thursday, October 1, at Dillon Ridge Marketplace, 318 Dillon Ridge Road. In Frisco, the new McDonald's at 960 North Drive started serving the week of September 1 and is Summit County's first fast-food restaurant open 24 hours. In Silverthorne, the former Bakers' Brewery building sold September 18 and could eventually house multiple businesses. The new operators and an opening timeline haven't been announced.

Opening day runs on the same weather

Over at A-Basin, the snowmakers took the system out for a test drive on Friday, October 2. The resort's blog said water lines, pumps and fan guns all checked out, but temperatures need to drop further before snowmaking can get productive. Keystone's homepage still says "Opening Day, ASAP!" Last year, Keystone opened October 25 and A-Basin opened October 26, about two weeks after each started making snow, according to the Denver Post. Both resorts wait to set a date until conditions allow, since each wants to be the first in Colorado to open.

Mark these dates on the calendar:

1. October 7: 2026/27 pass prices go up, according to Breckenridge's pass page.
2. Whenever the cold settles in: Keystone and A-Basin open, with no date set yet.
3. November 5: Wake Up Breck at 7 a.m., with free coffee and commemorative mugs.
4. November 6: Breckenridge and Copper Mountain both plan to open. Vail Resorts calls Breckenridge's date planned and subject to weather.
5. November 28–29: Copper hosts men's Alpine World Cup super-G and giant slalom races. After Saturday's bib draw for Sunday's giant slalom, O.A.R. plays a free concert in Center Village.

There's plenty of hope riding on this winter. The Denver Post noted talk of a Super El Niño in the forecast and powderhounds hoping for a long, snowy season. That's a hope, not a promise, and Denver Water's September update doesn't guarantee any particular refill for Dillon. What's certain is the math. Dillon is expected to keep dropping until spring runoff begins. Every inch of snow that builds a base at Keystone or Copper this winter is also snowpack in the basin that feeds the reservoir. Systemwide, Denver Water's storage stood at 67% on September 28, against a 91% average. Whether Frisco Bay has a working boat ramp next June depends on the same storms that decide how soon the first chair spins.

For more on how the seasons shape life in the county, see our Summit County neighborhood page and our look back at what August looked like for the people who live here.

At Heather Christensen Real Estate, we'll keep tracking Dillon's level and the opening-day announcements as the snow comes in. Join my SE Aurora community to get those updates along with the rest of our Front Range and mountain coverage.