As temperatures start to drop, September reminds us that summer is at an end and fall is now here. Sunshine is predominant though as the month actually has the highest percentage of sun out of any month. Sunny days and clear, cool nights are the standard weather pattern for the month.
Normal highs on the first of the month are 82 degrees with a low of 53. By the end of the month we see those high temperatures drop to an average of 73 and the lows get to a chilly 42. Overall the month averages 62.4 degrees.
In some years summer hangs on as late as the end of September - right to the last day of the month. September 30, 1980 saw a record high temperature of 90 degrees. 97 degrees is the hottest temperature ever recorded for the month - that happening on four occasions, the most recently on September 1st and 5th in 1995. Interestingly enough, all but four days of the month have recorded record highs in the 90s! The ones that haven't - the 21st, 22nd, 24th and 28th - have record temperatures pretty close of either 88 or 89 degrees. The chance for thunderstorms still exists in September but they are infrequent and severe ones are pretty rare.
All that sounds great for lovers of warm weather but winter too can make appearances in September - in fact, it can appear early on. The earliest measurable snow happened on September 3, 1961 when 4 inches of the white stuff fell at the old Stapleton International Airport and the mercury dropped to 33 degrees. The snowiest September on record occurred in 1971 which 17.2 inches of snow was recorded. Freezing has occurred in Denver as early as September 8, 1962 with a low of 31 degrees. Winter really hit home in 1985 when on September 29th, 9 inches of snow fell and Denver had a low of 17 degrees and a high of 29. Having said that though, in the 126 years since 1882, 81 Septembers have passed without a trace of snow.
In conclusion, September can bring just about anything but the odds due favor a beautiful month.
For More Information
Click here for the complete September 2008 preview including statistics and a look back at September 2007.
Temperature Normals and Extremes for September
Monthly Temperature, Rainfall and Snowfall Extremes for September
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