SUMMIT COUNTY — Warmer than average temperatures reigned through the end of September, marking a temperature trend that persisted throughout the past 12 months.
The average daily high in Dillon was 68.2 degrees, almost two degrees above the historic average (66.3 degrees), based on records going back to 1909.
The historic average daily low for September is well below freezing, at 28.7 degrees.
But this year’s lows for the month averaged to 34.1 degrees, as measured by Denver Water for the National Weather Service.
The local trend is in line with several climate-change models that predict warmer night time temperatures in the mountain region, a trend with serious implications for snowpack, runoff and potentially even for snowmaking operations at ski areas in the region.
The high temperature for the month was 77 degrees (Sept. 1).
The mercury climbed into the 70s frequently (17 days), and there were only three days when it didn’t hit 60 degrees.
On the low end, the Dillon station didn’t see a frost until Sept. 18. The coldest temps came Sept. 26-28, with a low of 25 degrees on all three nights.
Precipitation at the Dillon observation site was near normal in September, 1.4 inches, as compared to the historic average 1.34 inches.
October is one of the driest months of the year, with average precipitation totaling only 1.07 inches, although the month often sees the season’s first significant accumulation of snow, with an average 7.7 inches of the white stuff.
Weather statistics for Breckenridge were not available as of Sept. 2.
Seasonal outlook
Most climate models are showing development of mild La Niña conditions.
That cooling of sea surface temperatures in the Eastern Pacific makes it tough to predict snowfall for Colorado. Generally, the emergence of La Niña means that Colorado should be headed for a near average winter season in terms of precipitation.
The Climate Prediction Center is calling for above-normal temperatures through at least December across all but the very norther reaches of the state.
Perhaps continuing through the winter if La Niña conditions persist.
The bottom line shows a continued tendency toward dry conditions in Arizona and eastern Colorado, with a good chance for near-normal snowfall in the mountains of Colorado, according to climatologist Klaus Wolter.
If the La Niña weakens, it may allow for more fall and winter moisture in Arizona, New Mexico and eastern Colorado, all areas afflicted by an on-going drought, Wolter concluded in a forecast posted on the National Oceanic and Atmospheric Administration website (www.cdc.noaa.gov).
