Rain once again fell from sky in September

Finally, a significant rainfall at autumn’s start, 0.9 inches Sept. 23. That led six days in a row of precipitation totaling 1.4 inches for 82.8% of the month’s 1.8 inch total. The other 0.3 inches fell Sept 3-4, with a quarter inch of rain the 4th.

The 1.8 inches of rain is one of four years that has occurred since 2000, making it the tenth wettest September in the last 24 years and about average for this century.

The September rainfall average for this century has been pushed down to 1.9 inches. This year’s rainfall is the closest to average for its month in 2023.

Fourteen Septembers there have had less than two inches of rain, including 2016-2018 when between 1.3 and 1.6 inches fell.

The 3.2 inches in 2021 was a very different story and one of four years over three inches came down. The 5.2 inches in 2019 is the century’s record rainfall.

Last year’s 0.02 inches is by far the lowest amount of September moisture.

Rainfall has been below average every month of 2023. The 12.2 inches to date is 7.9 inches below the century average of 20.1 inches for January-September.

As fall approached, morning low temperatures fell, with three days below 39 degrees. Sept 21’s 38.2 degrees was the month’s low. It was 39.6 degrees Sept. 22 and Sept. 30 dipped to 38.6, a record for that date. The 42.8 degrees low Sept. 9 was a record for the date.

The 47.7 degrees average daily average low was 1.1 below the century’s average.

The temperature topped 80 degrees Sept. 2, at 81.2 degrees. Only two other days rose above 78 degrees, 78.1 Sept. 10 and 79.3 degrees Sept. 16.

There were 12 days above 70 degrees that helped to raise the month’s daily average maximum temperature to 68.6 degrees, 0.4 degrees above the century’s September high.

Ten mornings were below 45 degrees.

September’s monthly daily average temperature of 57.4 degrees was 0.6 degrees below the century’s average of 58.1 degree.

records

Measurements and data are at Washington State University’s Mount Vernon weather station on Memorial Highway.

Rain Report: September

Rain last week, Sept. 24-30: 0.46

Rainfall in Sept: 1.8

Number of rain days: 12

Least rain, one day: 0.01, 20th, 26th

Most rain, one day: 0.92, 23rd

Year least rain: 0.02, 2022

Year most rain: 5.24, 2019

Average rainfall, Sept. 2000-2023, 1.9

Rainfall in, August: 0.5

All totals in inches.

Data from WSU Mount Vernon.