Front Range Fans

Month-to-date precipitation through October 25 at Boulder stands at 1.7 inches, 0.7 inches above the normal of 1.03 inches for this date. This marks a sharp reversal from the preceding water year (October 2025-September 2026) which totaled 10.65 inches, tying the driest on record, yet the annual deficit persists.

Boulder station recorded 1.7 inches of precipitation in the month to October 26, 0.7 inches above normal for this date, but October 2025 in Boulder County averaged only 0.9 inches, 0.6 inches below the 1901-2000 normal of 1.4 inches. The county's October precipitation ranks 42nd driest in 131 years of record.

A threatened Great Spreadwing damselfly was observed on October 12 at 9th Street and Arapahoe Road in Boulder, Colorado, confirming continued presence of this sensitive species late in its flight season despite ongoing drought stress in the region.

Boulder County moved from 24.07% classified in Exceptional Drought (D4) in the week ending October 19 to 0% D4 in the current week of October 20-26, though 100% of the county remains in Extreme Drought (D3) or worse. This slight improvement provides modest relief from the most severe drought conditions that concentrate pollutants and depress streamflow.

A North American river otter was recorded on October 19 in Longmont, over 40 km north of the main Front Range study area. The species is state-threatened in Colorado and has reestablished on the Front Range since 2013 after reintroduction from 1976 to 1991; current drought conditions threaten riverine habitat that this recovering species depends on.

American black bears were sighted in Boulder city limits on October 21, October 19, October 15, October 14, and October 11. Bears moving into developed areas during autumn often coincide with stress periods when natural food sources become scarce; the extreme drought now covering Boulder County may be intensifying this pressure.

New England aster shows open flowers on 2026-10-23 near Boulder. This late-season bloom provides critical nectar for pollinators including monarchs fueling up for fall migration. The species is ranked imperiled (S2) in Colorado.

Evening Grosbeaks were recorded at Plaster Reservoir on 2026-10-22 with up to 2 individuals, and on 2026-10-24 at another location with up to 5 individuals, both confirmed by regional eBird reviewers. These sightings reflect an extreme irruption underway across the Interior West driven by widespread failure of ponderosa, limber, whitebark and pinyon pine crops; Type 1 Evening Grosbeaks are moving out of interior mountains into lowlands throughout the region in numbers at the upper end of recorded magnitudes.

PM10 readings at Denver-Boulder reached AQI 62 on September 24, indicating Moderate air quality. While ozone and fine particulates remain Good, coarse particulates are elevated above the Good threshold, likely from active wildfires burning in central and southern Colorado at varying containment levels.

Mean daily high and low temperatures over the past 30 days at the nearest reporting station (Boulder, CO) are running 6.1°F above normal, with average highs of 86.7°F against a normal of 80.6°F. This sustained heat stress combines with the severe drought to accelerate fuel drying and increase wildfire risk.