Thanks to a powerful push of warm and moist air on Thursday, temperatures soared and topped out at 61 degrees for Des Moines, which is two degrees short of a record. This high temperature was more than two standard deviations warmer than the average high (two sigma). The featured chart presents the combination of two sigma days against the average high and low temperature for December. The green symbols and lines are the values for 2010. The symbols are offset slightly for readability. The chart shows what one may intuitively expect, that cold months have a number of very cold days and vice versa. This year shows up as a somewhat rare combination of having a below average month along with an above two sigma warm day (yesterday).

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Good = 53
Bad = 24

Tags:   dec  

The featured chart presents the Iowa average December temperature along with a 30 year moving average. Five out of the past six years have seen well below temperatures, but nothing compared to 2000 or 1983. The moving average shows that the general trend has been for colder Decembers. Clicking the image will give a view back to 1893.

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Good = 25
Bad = 3

Tags:   dec  

The start of December has been on the cold side with an average of just 20 degrees for Ames so far. The featured chart presents some hope for warmer weather comparing the first 8 days of December versus the remaining 23. The cold starts most frequently see warmer weather for the remaining period, but only a few are above the overall average (blue dash). The far outlier to the left in the image was 2005, where the average temperature was only 6 degrees for the first 8 days of December. Thankfully, above freezing temperatures are expected today and tomorrow.

Voting:
Good = 17
Bad = 6

Tags:   dec