The end of summer came amid typical temperatures for September and a month rich in rainfall, thanks to one particularly wet day.
According to preliminary data received by the National Weather Service in Pendleton, the average temperature for last month was 65.4 degrees, which was 0.2 degrees above normal.
High temperatures averaged 75.5 degrees, which was 2.4 degrees below normal. The highest was 93 degrees, on Sept. 5. Low temperatures averaged 55.3 degrees, which was 2.7 degrees above normal. The lowest was 34, on Sept. 29.
Temperature exceeded 90 degrees on just two days for the month.
September precipitation totaled 1.48 inches, 0.73 inches above normal. Measurable precipitation — at least 0.01 inch — was received on nine days, with the heaviest rain, 0.94 inches, reported Sept. 8, the day after the highest recorded wind gust of 32 mph.
Precipitation this year has reached 12.76 inches, which is 1.07 inches below normal. Since October, the water year precipitation at Walla Walla has been 18.12 inches, which is 2.73 inches below normal.
The outlook for October from NOAA’s Climate Prediction Center calls for below-normal temperatures and near to above-normal precipitation. Normal highs for Walla Walla fall from 71 degrees at the start of October to 56 degrees at the end of October. Normal lows fall from 48 degrees to 39 degrees. The 30-year normal precipitation is 1.68 inches.