SeaTac recorded the driest May-June combination in 73 years, the National Weather Service reported Sunday.

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There’s an old saying in Seattle, born from a long history of soggy Fourth of July picnics: Summer doesn’t start here until July 5.

But this year, the cool, drizzly weather the region has seen over the past several days is expected to give way to warmer, sunnier conditions for the holiday.

“We should be seeing high temperatures getting up into the upper 70s, near 80 for the fourth,” said Jeff Michalski, meteorologist at the National Weather Service.

Cloudy skies and highs in the upper 60s are expected for Monday, but by Tuesday, any precipitation should be restricted to the coast and mountains, he said. The warmer weather should last at least through Thursday.

Old sayings notwithstanding, summer technically began on June 21. Still, the Puget Sound region typically doesn’t start experiencing the season until around July 12, Michalski said. That’s when a high-pressure area in the eastern Pacific intensifies and parks itself far enough north to deflect most weather systems away from Washington, setting the stage for sunny, dry conditions that usually extend into September.

But 2018 has already broken one record for aridity, the National Weather Service reported Sunday. The weather station at Sea-Tac Airport recorded the least precipitation since 1945 for the combined months of May and June, a scant 0.12 inch in May and 0.63 inch in June.
This year was only the third time that Seattle, where records go back more than 120 years, got less than an inch of rain in May and June combined. The other dry years were 1932 and 2015.

The month of May this year had marked a warmth record at Sea-Tac, with a median temperature of 61.1 degrees and one day when the high reached 88 degrees.