Seattle's 'June Gloom' explained: Why it tends to be so gray this time of year

June gloom.


It seems like every June brings gray skies instead of summer sunshine.

Q13 News Meteorologist M.J. McDermott says the term “June Gloom” is widely used in California where the pattern of morning clouds with partial afternoon clearing is a popular term from Santa Barbara to San Diego.

The reason is the combination of cold ocean water making fog and a ridge of high pressure keeping the atmosphere stagnant so that the low marine clouds can just hang around, rather than being blown away or dissipated.  That can happen in Western Washington as well.

For us, a gloomy June or “Juneuary” is simply our climatology – or what’s normal for this time of the year.  At our latitude and location next to the Pacific Ocean, it can take time to transition to summer weather.

That’s why we have the joke that Summer doesn’t begin until July 5th, even though the first day of summer is June 21st.   However, that has been changing the last few decades.

It’s warmer and sunny earlier in June and we have had rain-free Independence Days more often that wet ones.  In fact, since the year 2000, there have only been two July 4ths with measurable rainfall at SeaTac Airport.

This year, we may be starting out with some June Gloom or a bit of Juneuary, but the “Long-Range Prognostics” from the Climate Prediction Center say that we will have “above-normal” temperatures and “below-normal” precipitation out to June 14th.

As for the 4th of July . . . too soon to tell!