Denver, CO – June 6^th, 2025 – Colorado’s snowpack is nearing its seasonal end. Melt-out is occurring ahead of schedule across most of the state. Statewide snowpack is at 54 percent of normal. Snow water equivalent (SWE) statewide declines rapidly and most high elevation sites are now melted out, with only isolated locations primarily in northern basins retaining measurable snowpack. Statewide snowmelt is tracking 10 days earlier than median based on historical trends. The San Juan Mountains and Sangre de Cristo Range show a more pronounced signal. Many sites record snowmelt onset dates 20 days or more ahead of median. Southern sites already hampered by a meager accumulation season experienced accelerated melt due to persistent warm temperatures through May. Sites in the Front Range and near the divide have held onto snow slightly longer and are closer to normal melt-out timing.

May brings a welcomed reprieve from dry patterns. Totals rank second highest for the water year to date (WYTD), behind only November. WYTD precipitation is at 86% of median statewide with May at 96% and outperforming traditionally stronger accumulation months like December, January and April. Despite lower climatological averages for May, precipitation was most favored in the San Juan Mountains, Sangre de Cristo Range and the Front Range. 

Early June storms extend the trend from May, delivering over 2 inches of precipitation at SNOTEL sites in the southwest between June 2 and June 5. Precipitation patterns shift toward higher humidity, more persistent cloud cover and frequent showers. These early June rain events align with the onset of the North American Monsoon, which often delivers afternoon storms and elevated atmospheric moisture, a vital source of summer water supply in southern Colorado.

Historically, 7% of annual precipitation falls during May, while June through September account for nearly 30% of annual accumulation in basins like the San Miguel-Dolores-Animas-San Juan (SMDASJ) and Upper Rio Grande (URG). A strong early start to the monsoon improves soil moisture, support reservoir levels and reduces wildfire risk as runoff tapers.  That said early monsoon activity also raises concerns about short-term risks. Flood watches have already issued for portions of the southwest. 

Observed streamflows reflect a compressed runoff season, particularly across the Western Slope. “Early snowmelt combined with limited snowpack has resulted in lower runoff forecasts, particularly in southern basins,” notes Nagam Bell, NRCS hydrologist. “Early monsoon activity could improve moisture conditions but consistent summer rainfall will be critical moving forward." Southern and western basins run at approximately 50% of average flows for early June. Northeastern regions, benefitting from slightly better snow retention, track closer to seasonal norms but remain below median. 

Streamflow forecasts for the remainder of the runoff period reflect below normal runoff particularly west of the Continental Divide. Forecast departures from normal are concentrated across the Western Slope where the largest deficits are observed. At the Colorado River near Cameo the forecast volume is 391,000 acre-feet below normal. Upstream of the Colorado and Gunnison confluence the Gunnison River near Grand Junction forecasts a volume 351,000 acre-feet below normal. Statewide the average forecast percentile at the 50% exceedance probability is near the 22^nd percentile based on 80 forecast points. The median forecast across the state is 67% for the 30-year median, with a majority of forecast points between 50% to 75% of median. Outlooks near major reservoirs including inflow into Pueblo Reservoir, Colorado River below Lake Granby and the Blue River below Dillon Reservoir are below median but generally near seasonal norms. By contrast, the Gunnison River inflow to Blue Mesa Reservoir is forecast at 64% of median and the Dolores River above and below McPhee are forecast near 60% of median. Forecasts point to continued low runoff volumes for rivers across the Western Slope, while flows in the Front Range and north central regions remain closer to median conditions. 

Statewide reservoir storage holds at 89% of median as of June 1. This marks a modest decrease from 93% a year ago. The Arkansas, URG, Gunnison, Colorado Headwaters and South Platte maintain near to above median storage ranging from 92% to 107% of median. The SMDASJ continues to trail at 74% of median with McPhee Reservoir at 66% capacity and 70% of median. These storage levels become increasingly important as snowmelt contributions diminish and summer water demand increases.

Colorado is shifting from snowmelt to summer moisture. While early runoff and below normal snowpack limit streamflow the recent precipitation and early monsoonal activity provide cautious optimism. NOAA’s seasonal outlooks forecast above normal precipitation for Colorado through the 6-10 day and monthly periods, with the southwest showing the strongest signal for wetter conditions. Temperatures are forecast to trend above normal statewide. 

Colorado’s Snowpack and Reservoir Storage as of June 1^st, 2025

* San Miguel-Dolores-Animas-San Juan River basin

* *For more detailed information about January mountain snowpack refer to the June 1st, 2025 Colorado Water Supply Outlook Report. For the most up to date information about Colorado snowpack and water supply related information, refer to the Colorado Snow Survey website.