Question:  In Steamboat, is the snow accumulation during December different during La Niña Years?

In September, 2017, NOAA issued: La Niña is likely (exceeding ~80%) through the Northern Hemisphere winter 2017-18, with a transition to ENSO-neutral most likely during the mid-to-late spring (

According to Golden Gate Weather (, La Niña Years can be ranked as strong, moderate, or week depending upon measured pressure differences.

We categorized and graphed the snow accumulation in Steamboat Springs (snow data from NCDC – National Climate Data Center) as strong, moderate or weak.

Snow depth in Steamboat Springs typically increases through December (all years).  Interestingly, during La Niña years the snow accumulation during the first part of December is lower than average.

Daily Maximum December Snow Depth Compared to La Niña Years





Steamboat Springs – 2017 Hotter than Usual November or Typical November Weather Pattern?

As ski season approaches, snow accumulation becomes more anticipated.  The end of November 2017 in Steamboat Springs was disappointing as far as snow was concerned.  A question that arises:  What is the record of temperature and snowfall at the end of November? Should the city, county, and residents plan for significant snow at this time? Has snowfall and snow accumulation changed over time?  Is temperature showing significant change over time?  The National Climate Data Center collects and archives climate data for several sites around Steamboat Springs.  The data is publicly available at  Keep in mind that the data in this post originates from a site in Steamboat Springs.  The temperature and snow data on the  ski mountain may not exactly match the temperature and snow data for the town.

End of November Temperature Data


End of November Maximum (orange) and Minimum (blue) Temperature (°F average for Nov 23 to Nov 30).

Average weekly maximum temperature: decreasing

Average weekly minimum temperature : increasing

The temperature observed in Steamboat Springs, CO for the last week of November shows changes.   The average weekly maximum temperature appears to be decreasing (over the past century).  Notice the general low maximum temperature in the 1960’s to 1990’s.  If we investigated the past 60 years, we might interpret the maximum average weekly temperature to be increasing.  Also note the range from 20°F to 55°F of average maximum weekly temperature with a current average of ~ 35°F.  The average weekly minimum temperature appears to be increasing over the past century.  The range in average weekly minimum temperature also appears to be decreasing (it’s not as cold as it used to be) – particularly since the 1960’s.

End of November Snow Data

End of November (Nov 21 to Nov 30) snowfall (inches)

Snowfall during the last week of November, over the past century, has increased from 5 inches to 10 inches.  Although the snowfall has increased, a significant year to year range exists.  It is still common to experience no snow during the last week of November.  Additionally the maximum temperature of the week is illustrated by the color of the data points.  An interesting observation, when the maximum temperature experienced reaches 55-61°F, the likelihood of snowfall is low. Another plot that helps to elucidate this relationship is a Maximum (Max) Temperature to Maximum Snow Depth plot.

End of November – Maximum Temperature to Snowfall comparison

In the graph above, the End of November max Snow Depth is zero when maximum temperature rises above 55 °F.


Looking at the overall decline in End of November maximum temperature (above), this is good news for snow enthusiasts.


What above the weekly maximum snowdepth data?

We can look at weekly snowdepth for the last week of November and the 1st two weeks in December to get an understanding how snowdepth has historically evolved.  The graphs below suggest that it is fairly common to have no accumulated snow in Steamboat Springs during the last week of November.   By the 2nd week of December, Steamboat Springs experiences at least 3-6 inches with average 15 inches of accumulated snow.  Not since the early 1960’s has the accumulated snow depth been zero during the 2nd week of December.


End of November (last week) maximum Snow Depth (inches)


1st week of December Maximum Snow Depth (inches)


2nd week of December Maximum Snow Depth (inches)


Average annual snowfall and snow depth

For an average year, November (11th month) receives 12% of the annual snowfall.  This does not necessarily translate to the snow depth (or accumulated snow).  Snow depth only increases if the snowfall does not melt or sublime.  January (1st month) receives 21.4% of the annual snowfall; February – 18.1%; March – 14%; April – 8.1% and December 20.4%.

Percentage of snow per month (1 = January, 2 = February, 3 = March, 4 = April, 5 = May, 6 = June, 7 = July, 8 = August, 9 = September, 10 = October, 11 = November, 12 = December)


Throughout the yearly snow season, the average weekly snowfall typically begins in about week 40 or October and progressively increases through February to March.  The end of November (week 47, 48) typically experiences a few inches of snowfall.

Average snowfall per week throughout the year (inches)


The average snow depth (accumulation of snow) peaks in the middle to end of February and beginning of March (weeks 6 to 9).  Note the snow depth at the end of November (weeks 47, 48) is between 0 and 7.5 inches.

Weekly proportion of average snow depth throughout the year. For example, 1 = first week of January, 8 = last week of February, etc… End of November = weeks 47 and/or 48.



The climate indices of temperature and snowfall or snow depth for 2017 do not appear to be dramatically different than the historical record.  Steamboat Springs typically does not experience a large accumulation of snow until middle to late December. Historically, the end of November displays a wide range of temperature and snow conditions.  The climate records underscore the conventional wisdom of local and long-time residents.