IEM Daily Feature
Thursday, 02 December 2010

When does winter start?

Posted: 02 Dec 2010 05:48 AM

While yesterday was the start of meteorological winter, the 21st is the start of the commonly defined winter season. If one considers winter a 91 day period with the coldest climatological temperatures, the actual start of winter is slightly before 1 December in Iowa. The feature map presents an IEM produced analysis of the start date of the coldest 91 consecutive day period based on climatology data. The map nicely shows the start of this period comes first for those in the western US and marches east with a ~4 week difference between the two. The coastal regions of California enjoy the moderating effects of the Pacific Ocean and appear to be the last to join the winter period.

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Tags:   winter   temp