Cooler weather, shorter days in store for Cannon

By Jim Robinson, meteorological tech: 27th Special Operations Support Squadron

September begins the gradual but perceptible transition from summer into autumn and features some of the most pleasant weather conditions of the year here. Qualitatively speaking, the typical summertime pattern of relatively frequent late day thunderstorms diminishes through the month as the sun’s influence wanes. Conversely, a typically autumnal pattern of increasing synoptic influence, characterized by about three or four strong cold fronts during the month, strengthens. The strong cold fronts often feature temperature drops of 20 to 25 degrees Fahrenheit in a couple hours and winds speeds that 58 mph. The highest recorded wind gust in September is slightly more than 80 mph.

The autumnal equinox occurs Sept. 22, and marks the start of astronomical autumn. Before the equinox, the northern hemisphere receives an average of more than 12 hours of sunlight daily. After the autumnal equinox, the northern hemisphere receives less than 12 hours of sunlight daily. The amount of potentially available sunlight deceases by 62 minutes from Sept. 1 to Sept. 30. The time of sunrise gets later by 21 minutes during September, ranging from 6:26 a.m., on Sept. 1 to 6:47 a.m., on Sept 30. Sunset gets earlier by 41 minutes through the month, hence, the region loses more sunlight in the evening than it does in the morning.

Quantitatively, the average temperature for September is 69 degrees, ranging from 73 degrees on Sept. 1 to 64 degrees on Sept 30. The average maximum temperature for the month is 82 degrees, with the average daily maximum temperature ranging from 86 degrees on the first day of the month dropping to 78 degrees by Sept. 30. The average minimum temperature for the month is 55 degrees, with the average daily minimum temperature cooling from 60 degrees on the 1st to 50 degrees on the 30th.

The highest recorded monthly temperature is 105 degrees, which occurred Sept. 2, 1937. The lowest temperature recorded is 31 degrees, which occurred on the Sept. 30, 1945. Daily record high temperatures are mainly in the low 100s in the first half of the month, but generally stay in the 90s during the second half of the month. Daily record low temperatures are generally in the 40s in the first half of the month, but dip into the 30s during the second half of the month.

Cannon averages 1.8 inches of precipitation during September. This is less than the 2.8 inch average during August, but more than the 1.4 inch average of October. This is indicative of the waning influence of thunderstorms, which can dump large amounts of rainfall in a short time, and the increasing influence of frontal systems that are generally associated with lesser precipitation amounts.