Chains are required.
Chains are required. Kris Wiktor/shutterstock.com

Mount Rainier and Olympic national parks are free to visitors today. (The Olympic National Park Visitor Center and the Hoh Visitor Center will be open to 4 p.m. The road to Mount Rainier is also open till 4 p.m., and requires chains.) Why aren't any state parks free? I don't know, because no one is answering the phones over there. But in Colorado, all 42 state parks are free today.

If you can't make it to a park today (maybe you're, uh, working?), Washington State Parks is offering 16 free days next year.

January 1 – (Thursday) New Year’s Day and State Parks’ First Day Hikes Day
January 17 and 18 – (Sunday and Monday) Martin Luther King Jr. Day
March 19 – (Saturday) Washington State Parks’ 103rd birthday
March 26 – (Saturday) A springtime free Saturday
April 22 – (Friday) Earth Day
May 8 – (Sunday) A springtime free Sunday
June 4 – (Saturday) National Trails Day
June 11 – (Saturday) National Get Outdoors Day
Aug. 25 – (Thursday) National Park Service 100th birthday
Sept. 24 – (Saturday) National Public Lands Day
Nov. 11 – (Friday) Veterans Day