Weather consultant Chuck Otte has announced that September continued the hot and dry trend that has been in place for much of 2023.
Temperatures were well above normal and monthly rainfall was one half of normal. The average daily high for September was 86.9, 6.5 degrees above normal. The average overnight low was 63.0, 5.5 degrees above normal. This gave us a monthly mean temperature of 75.0, 6.1 degrees above normal. This thrust September 2023 into the enviable position of the fourth hottest September on record (records dating to the late 1940s.)
The hottest September was in 1954 with a monthly mean temperature of 78.1 and an average daily high of 92.1. More concerning though is that of the five hottest Septembers on record, three of them have been since 2019 (2019, 2021, and 2023). The coldest September was in 1974 with a monthly mean temperature of only 61.1.
Surprisingly there was only one temperature record set during the month. The overnight low of 79 on the 5th broke the high low record for that date. The old record was 76 set in 1990 and again in 2016. The highest temperature for the month was the afternoon high of 100 on both September 2nd and the 3rd. The lowest temperature for the month was 54 on the morning of the 13th. While average low temperatures in September range from the low 60s to about 50 degrees, it is common to have a few overnight temperatures in the 40s, which we did not see this year.
This is the sixth consecutive month with temperatures above normal. So far in 2023 we have had only one month with monthly mean temperatures below average. That was March and the temperature was only 0.1 degree below average. Average rainfall for September is 2.85 inches. The area received only 1.68 inches for the entire month. A rainfall event of 1.18 inches on the 22nd was the highest 24-hour rainfall event since the 5th of July when 1.80 inches of rain fell.
Year to date we have received 21.04 inches of precipitation, which is only three fourths of our normal, which is 28.50 inches. The wettest September on record was in 1967 when 13.28 inches of rain was recorded. The driest September on record was in 1947 when 0.24 inches of rain fell. October brings us our first full month of autumn, and often our first freezing temperatures. Average daily highs start the month around 75 and by Halloween are down to a cool 61 degrees. Average overnight lows drop from 51 on the 1st to 39 on the 31st. Average precipitation during October is 2.48 inches. Long-term average snowfall for October is one tenth of an inch, but October snowfall events are few and far between. Since 1951 the average first frost date has been October 19th but has occurred as early as September 17th and as late as November 13th.