"January's warm weather in Western Washington might set a record.

Through Thursday, the average temperature at Seattle-Tacoma International Airport was 46.9 degrees. That would top the record of 46.6 degrees set in 2006. Records have been kept there since 1945.

In a typical January, the average temperature at the airport is 40.9 degrees. The average high temperature is 47 degrees. That means this January’s average temperature is close to the average high temperature for the month in previous years.

Many cities in Western Washington – including Olympia – are also close to records for January. The warmer-than-normal weather largely can be attributed to El Niño, a cyclical warming of the equatorial Pacific Ocean," quoting The Olympian.

UPDATE, fEBRUARY 1, 2010:
"Warmest January on record for Seattle"
"2nd warmest in Olympia"
From The Olympian