Weather Blog

Seattle sets a record for coldest April on record

Seattle sets a record for coldest April on record
Visibility web camera shows a grey Seattle on April 25, 2011. (Image courtesy: Puget Sound Clean Air Agency)

SEATTLE -- It might have been gorgeous on Saturday, but it was too little too late.

Seattle officially set its record for having the coldest average high temperature for April. The average high this year was 52.23 degrees, well below the record of 52.6 degrees set in 1970. Put another way, it was cumulatively 11 degrees colder this month than it had ever been before.

Here are the Top 5 coldest Aprils at Sea-Tac Airport:

  1. 52.23 degrees in 2011
  2. 52.6 degrees in 1970
  3. 52.83 degrees in 1955
  4. 53.53 degrees in 1954
  5. 53.6 degrees in 1967

But even if you factor in the Downtown Federal Building records, which go back to 1891, that gauge's record coldest April was also 52.6 degrees, set in 1917.

This month also "featured" nine days in the 40s -- including a record seven straight days below 50 to begin the month. The warmest day of the month was 66, and it was the only day in April that crossed 60 degrees -- yet another record as before the fewest days above 60 in April was two, set in 1954.

In fact, it was so chilly in April, that it was on par with the average high temperature...for March (52.2)

The normal average high temperature in April is 57.4 degrees. The warmest is 63.1 degrees set in 1977.

Seattle's overall average temperature was not quite a record

While we easily set the record for coldest average high temperature, we came up a bit short in setting the record for overall average temperature, which factors in high and low temperature.

This month, the average high temperature was 45.53 degrees, which puts us in a virtual tie with 1948 for second-coldest April. The record was 44.6 degrees set in 1955. While 1955's average high was a little warmer than 2011, that year had much colder overnight lows.

It was really wet too...

In addition to setting the temperature record, we were high up the charts for it being the wettest April on record. The month tallied 4.47" of rain -- good for fourth-wettest April on record behind 1991 (6.53"), 1996 (5.37") and 1993 (4.54").

That came courtesy of 20 days of the month's 30 recording measurable rain, fresh off the heels of March's 24-of-31 days with rain too.

Overall, spring has been gloomy

When you combine our record chilly April with our fairly chilly March, we find that 2011 is the seventh-coldest March-April on record with an average high of 52.0 degrees. The record is 1955 at 49.5 degrees, which featured the coldest March on record. (In fact, 1955 was the coldest overall year at Sea-Tac Airport.)

For rain, it was the fifth-wettest March-April at Sea-Tac Airport at 10.76", just off the record of 12.47" set in 1997.

(Incidentally, 1955 was the 25th wettest March-April, so while it was certainly colder then, it wasn't nearly as wet as this stretch. 2011 wins for gloomier spring?)

And, of course, sunshine was in short supply. While we broke a streak of 56 straight days without an official sunny day on April 23, the overall average sky cover for March and April was 80.1%.

Well on our way to not making the same claim for May

May is starting off sunny and warm and while long range forecasts do still show some occasional bouts of cool, showery weather -- Monday and Tuesday we go right back into ice box with another cold weather system -- it doesn't appear it'll be as relentless as April.