Colorado’s Water Year 2026: Warmest on record, by a wide margin, with the lowest snowpack ever measured

The Colorado Climate Center (CCC) released its Water Year 2026 (WY2026) in Review on Tuesday, Oct. 20 and the verdict is in; it was hot, it was dry, and it was a rough year.

From Oct. 1, 2025 to Sept. 30, 2026, Colorado recorded its warmest water year on record, by a substantial margin, it recorded one of its driest years, and during WY2026 became the lowest mountain snowpack ever recorded.

The report compiled by the CCC at Colorado State University, with Engagement Climatologist Allie Mazurek as lead author, covers a year the center says “strained water supplies” and “fed widespread drought,” with impacts to agriculture, wildlife, human health and recreation.

A water year runs Oct. 1 to Sept. 30 because it follows the path of water through the West.

Snowpack builds in winter, melts in spring, feeds streams and reservoirs in summer, and is then used by crops through the growing season.

Notable highlights:

• Warmest water year in 131 years of records: 4.5°F above the 1991-2020 average and more than 2°F warmer than the previous record year of 1934.
• WY2026 was the 18th-driest water year statewide; January-March was the 4th-driest on record.
• Record warmth was recorded in December, February, March and August, plus the warmest winter, spring and summer were recorded.
• 286 days were above average temperatures, and only 79 were below, plus 75 days ran at least 10°F above average.
• Statewide snowpack peaked at just 51% of average, approximately a month early.
• 60 of 64 long-term snow course sites reported 50-year lows on April 1.
• Colorado reservoirs ended the year more than 2 million acre-feet below average, the lowest since 2002.
• Seven statewide heat waves, the most in any year since records began in 1951.
• Water year ended with drought coverage worse than it began: 82% of the state in drought on Sept. 29, versus 45% a year earlier.
• St. Mary’s Glacier melted out completely in mid-September.

A year of temperature superlatives

First off, the warmth wasn’t confined to one season, where four months set statewide records.

December was +8.9°F above the 1991-2020 average, February was +7.6°F, March was +9.8°F and August was +4.1°F.

In some locations, the water year averaged 2.5°F to 3°F or more above the previous record. The CCC noted that the gap between first-place 2026 and second-place 1934 is as large as the gap between second place and 24th.

The daily tallies were just as lopsided as the monthly tallies.

For every below-average temperature day, there were about 3.6 above-average temperature days, and nearly half the year (165 days) ran at least 5°F above average.

In gridded data, daily warm records outnumbered cold records 21.7 to 1; the most unbalanced ratio ever recorded. At individual stations the ratio was roughly 14 to 1, compared with about 2 to 1 the year before.

Notable heat markers from the report:

• July 27 was the hottest single day on record statewide, at an average of 78.88°F.
• The nine warmest March days on record all occurred in March 2026.
• Several hundred stations set new monthly March records, some by as much as 10°F, and in some places March highs topped all-time April maximums going back to 1951.
• Denver logged 18 days of 60°F or warmer in December, beating the 1980 record of 15.
• Ninety-degree days piled up: Burlington had 90 (average 49), Montrose 77 (35), Cortez 75 (41), Boulder 57 (33), Fort Collins 54 (30), Alamosa 24 (4) and Steamboat Springs 29 (6).

Dry, when it mattered most

Statewide, the year ranked 18th-driest, but the pattern did the damage.

From January through March, the heart of the snow-building season, it was the 4th-driest on record and at least top-10 driest across most mountain areas.

April rains, crucial for crops and rangeland on the eastern Plains, came in far below normal alongside above-average temperatures, setting off a flash drought that produced four-category drought degradations in eight weeks across southeastern Colorado.

Two wet bookends masked how dry the middle was.

October 2025 brought more than eight inches of rain in some southwest Colorado locations, from the remnants of Hurricane Priscilla and Tropical Storm Raymond, pushing the San Juan River at Pagosa Springs to major flood stage twice, forcing the evacuation of the town of Vallecito.

September 2026 then ranked 5th-wettest.

Without the wet finish, the CCC says the first 11 months of the water year (October through August) would’ve ranked 6th-driest on record, and November through August, 3rd-driest.

In the northern Colorado city of Greeley, it recorded just 6.78 inches of precipitation, which was less than half its normal 14.62 inches of precipitation.

The lowest snowpack on record, then record-low stream flows

Statewide snowpack peaked at only 51% of average between March 8-10, about a month earlier than normal.

It then collapsed during the March heat wave, a melt the CCC compares to what Colorado normally sees in May or June.

On April 1, the snowpack stood well below all four of the state’s worst winter years: 1976/77, 1980/81, 2001/02 and 2011/12.

Sixty of 64 snow course sites, with at least 50 years of data, reported record lows. Some snow courses that had never before dropped below 4 to 6 inches of snow water equivalent on April 1 reported none at all.

Record-low streamflow was reported across the state, and cumulative flow on the Colorado River at Cameo ran worse than in 2002, and Blue Mesa Reservoir fell far below its previous summer low.

Lake Powell and Lake Mead hit record lows since filling, and total storage in Colorado’s reservoirs finished more than 2 million acre-feet below average, the lowest since 2002.

A May snowstorm did drop more than two feet of snow around Estes Park, the largest snow of the year for many Front Range residents, however, it had little effect on the overall snowpack.

Drought ended the year worse than it started

At the start of the water year, 45% of Colorado was in moderate drought or worse, and 14% in extreme drought or worse, all concentrated on the western side of the state.

Exceptional drought (D4) returned to the state on Dec. 23.

By the end of March, about half the state was in extreme or exceptional drought, and on April 28 the entire state was in drought, with 59% in extreme or worse at that peak.

Parts of Garfield and Pitkin counties spent 15 straight months in D3 or D4, and the statewide Palmer Drought Severity Index hit its lowest value on record at the end of August, slightly worse than 2002.

Unfortunately, relief came late. Rain in September cut drought coverage to 82% of the state by Sept. 29, with 35% in extreme drought or worse, still well above where the water year began.

A year of extreme events

• November: First snow arrived record-late in Boulder, Loveland and Evergreen, and second-latest in Denver, on Nov. 29.
• December: Downslope windstorms on Dec. 17-18 sparked fires on the eastern Plains that burned more than 10,000 acres.
• January: The year’s only real cold snap set several daily record lows in late January.
• March: A record-setting heat dome gave 10 western states their warmest March on record.
• June: Severe storms brought flash flooding and hail, with wind gusts above 100 mph reported in Akron on June 22.
• June-July: Wildfires ignited statewide. The Aspen Acres Fire, discovered June 29, grew past 35,000 acres in two days, and the Knowles Fire, near the larger Snyder Fire, killed four firefighters. Aspen Acres and the Ferris Fire rank seventh and tenth among Colorado’s largest wildfires by acreage.
• July-August: Flash floods and debris flows hit southwest Colorado, including burn scar areas.
• September: St. Mary’s Glacier, a semi-permanent snowfield known as a summertime ski destination, fully melted out in mid-September.