September is normally 9 degrees cooler than August. But with August being below normal temperatures this year, and September being above normal, the difference was less than ½ of a degree. Adding to that was the below normal rainfall that occurred during the month.
The average daily high for September was 82.7, 2.5 degrees above normal, and nearly a degree warmer than August´s average daily high. The average overnight low was 62.5 degrees, 6.5 degrees above normal. This left us with a monthly mean temperature of 72.6, 4.5 degrees above normal and only four tenths of a degree cooler than August. There were 7 days in September with temperatures of 90 or above, compared to only 4 in August and slightly above the long term average of 6. The highest temperature for the month was 94 on the 14th. The coolest temperature for September was 47 on the morning of the 27th. There were no temperature records set or tied in September, the second month in a row without any records. Fortunately we were quite a ways from being a record warm month. The hottest September on record was 1954 with a monthly mean temperature of 78.1. The coolest September on record was in 1974 with a monthly mean temperature of 61.1.
September continued a dry period that started after large rains in early August. The first two weeks of September saw no rain across the region and highly scattered rains dotted the area the last two weeks of the month. Average September rainfall is 3.28 inches. Milford Lake received 1.58 inches of rain and Junction City received only 0.76 inches of rain. Normal year to date precipitation through September is 27.96 inches. Milford Lake has received 30.57 inches so far in 2017 and Junction City has received 27.14 inches. The driest September was in 1947 when only 0.24 inches of rain fell. The wettest September was in 1967 when 13.28 inches of rain deluged the region.
October brings us many of the finer parts of autumn including cooler temperatures and often our first frosty weather! Average daily highs in October start the month at 76 and by the end of the month are down to 63. Overnight lows range from 50 on the 1st to 40 by Halloween. Rainfall continues to decrease as we move towards the end of the year. Average rainfall for October is 2.62 inches. The first chance of snow starts to creep into the region in October with long term average snowfall of 0.1 inches for the month. Our average first frost (official temperature of 32 degrees or lower) occurs on October 19th. Since 1951 that first frost has been as early as September 17th but as late as November 10th. Two years
out of three however the first frost will occur within 12 days of October 19th. Given the current long range forecast, it could very well be after the 19th this year.
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Chuck Otte
County Extension Agent, Ag & Natural Resources