Temperatures warmed nicely on Saturday into the 50s, placing us over a standard deviation from average for the date (called sigma). Temperatures have since crashed and will struggle in the single digits today, which less than negative one sigma from average. The featured chart looks at how often this change of going from at least a positive one sigma high temperature to lower than a negative one within three days. The top chart shows that January is the least frequent month for this event as warm air surges are the least common. The bottom chart presents the yearly total of these events and last year saw the second most at 12 days.

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Tags:   sigma   highs