Near record dry Seattle December caps below average precipitation 2013

Seattle-Tacoma Airport recorded only 1.66 inches of precipitation in December. This low total was the second driest December at the airport surpassed only by the record 1.37 inches set in 1978.

Going back to when Seattle weather records began in 1891 at the Federal Building, this was the fifth driest December behind 1.00 inches in 1944, 1.27 inches in 1943, and 1.39 inches in 1914.

There were only two days in December with measurable precipitation of a quarter inch or more. Including the Federal Building records, there have only been two Decembers with less than two days of a quarter inch or more precipitation – 1978 with one day and 1944 with none. December 2013 had no days with a half inch or more precipitation, which has happened only seven times in December since 1891.

In 2013, there were 152 days with measurable precipitation at Sea-Tac, matching the average number of days with measurable precipitation in a year. Yet only 32.56 inches fell at the airport, almost five inches below the annual average of 37.49 inches.

2013 was a year of precipitation extremes in Seattle. September was the wettest September on record with 6.17 inches, while April was the second wettest April on record at the airport with 5.89 inches. In contrast and in addition to the dry December, July tied a record as a driest July with only a trace of precipitation.

In 2013, there were only two stretches where precipitation was above average – January 9 through the 14 and September 6 through November 23 – a total of 85 days or less than a quarter of the year. 2013 was the first year on record going back to 1891 that September was the wettest month of the year. In addition, it was only the fifth time that April was the wettest out of the first four months of the year.

Statistics were compiled by Dana Felton of the National Weather Service Seattle.