FleaDates › Flea season › Washington › Seattle
Seattle · WA
When does flea season start in Seattle?
Flea season in Seattle typically runs late March to early November, peaking Jun–Sep. That's about 2 weeks earlier than the Washington statewide estimate — city warmth and lower elevation add up.
Ticks in Seattle
Local tick activity typically runs year-round, heaviest May–Oct. The species to know in Washington: western blacklegged tick, Rocky Mountain wood tick, American dog tick.
More on species and timing: Washington tick season.
Numbers come from NOAA U.S. Climate Normals (1991–2020) recorded at SEATTLE BOEING FLD — a climate-based estimate; real years wobble.
Frequently asked questions
When does flea season start in Seattle?
Around late March in a typical year, once local averages hold around 50°F. A warm spring pulls it earlier — prevention shouldn't wait for the calendar.
Is flea season in Seattle different from the rest of Washington?
Somewhat. That's about 2 weeks earlier than the Washington statewide estimate — city warmth and lower elevation add up. The statewide page averages several stations across Washington; this page uses the normals recorded at SEATTLE BOEING FLD.
Do dogs in Seattle need prevention outside flea season?
Yes — vets recommend year-round parasite prevention regardless of the local calendar. Indoor fleas ignore the weather entirely, and ticks in Washington are typically active mid-February to late November, a longer window than fleas get.