Conditions near Larkspur as published by the National Weather Servic
© National Weather Service
Snow near Larkspur
Snow has fallen in the Mile High City over nine straight months, spanning 245 days

A seemingly endless snow season has gripped the Mile High City, where flakes first flew in early September and fell again late Monday into Tuesday. A coating to a few inches of snow covered much of the Denver region Tuesday morning.

The snow accumulated mostly on grassy areas and caused few problems, but it extended one of Denver's longest snow seasons on record, spanning 245 days.

The first flakes of the season fell in the city on Sept. 8, when an inch fell just one day after high temperatures in the 90s. It was the first measurable September snow since 1994.

While small amounts of snow fell in October (four inches), November (five inches), December (seven inches) and January (3.1 inches), it wasn't until February that Denver really started to get dumped on.

"Seems like in February things seemed to turn around," said Jim Kalina, a meteorologist at the National Weather Service in Boulder, Colo. "February [with 13.5 inches of snow], March [34 inches] and April [12.6 inches] were all above normal."

Tuesday's snow came as temperatures plunged to near-freezing in the morning and were predicted to reach the low 40s in the afternoon, nearly 30 degrees colder than average.

The cold conditions in the Rockies is part of an unusual May weather pattern that has produced below-normal temperatures from Montana to northern Florida.

By itself, snow in May in Denver isn't terribly out of the ordinary. Measurable snow has fallen on May 10 or later there in seven of the past 15 years, tweeted Chris Bianchi, a meteorologist based in Denver.

But both the longevity of the season and the amount of snow that has fallen this time have been unusual.

The May snow comes after the city's second-snowiest March on record, when 34 inches fell. Denver has recorded 80.2 inches since September, which ranks among its top 20 snowiest seasons on record.

Including those first flakes in September, snow has fallen in the city for nine straight months.

2021 is off to an unusually white and wet start. Through Monday, Bianchi tweeted that Denver had received more total precipitation, accounting for both melted snow and rain, than Chicago, San Francisco and Detroit.

"This is remarkable — since Denver is just shy of desert status," he tweeted.

Adding in the rain and snow Monday night into Tuesday, Denver's 2021 precipitation has leaped to more than eight inches, nearly double its average year-to-date total.

Snowfall totals through Tuesday morning were even greater in the foothills west of Denver and in the high terrain west of Boulder, where up to 10 to 13 inches were reported and winter storm warnings were in effect. Estes Park, Colo., reported 8.8 inches. To the north, Cheyenne, Wyo., also under a winter storm warning, reported six to eight inches.

While many areas around Denver reported measurable snow, only a trace was reported at Denver International Airport, where the snow didn't stick. This means that while Denver's snow season reached 245 days on Tuesday, it won't enter the record book that way. If the airport had posted even 0.1 inches, it would have officially marked Denver's second-longest snow season on record, only trailing 258 days in 1974-1975. But with the last measurable snow occurring April 21 (2.6 inches), the snow season officially stands at 225 days long, which would tie for 10th-longest on record.

While unlikely, Denver's snow season may not be over. The city has seen measurable snowfall as late as June twice. In 1951, 0.3 inches fell on June 2, and, in 1953, 0.5 inches fell on June 5.

In the meantime, mild weather is returning to the city after today's winterlike chill.

"It will warm up," Kalina said. "Tomorrow we'll be into the low 60s. By Thursday, we'll be back into the 70s. Then it will be warm all the way out through early next week."