Calendar quarter.

RCW 50.04.050
in effect
Sign in to generate a plain English summaryAsk Belisarius Agent
"Calendar quarter" means the period of three consecutive calendar months ending on March 31st, June 30th, September 30th, or December 31st. "Calendar quarter" means the period of three consecutive calendar months ending on March 31st, June 30th, September 30th, or December 31st.
Source: WA Statutes (Official Site)URL: https://app.leg.wa.gov/RCW/default.aspx?cite=50.04&full=trueFetched: 6/29/2026

Starting a business in Washington? Washington LLC guide: costs and requirements