Green Lake is one of my three best places to enjoy the sun in and around Seattle. When runners talk about getting together for a run often it is Green Lake also you can find the premier runners shop on the perimeter of Green Lake. You can rent a bike from Gregg’s Cycle, paddle board, kayak, boat from Green Lake Boat Rentals. There are six restaurants around lake with great outdoor seating on sunny days and the PCC has a great deli for those days a picnic on a blanket fulfills your sunny day fantasy. Meeting a friend is easy at any of the six coffee shops. Green Lake is the safest place to enjoy yourself without the hassles of in city sun bathing. Bus service to Green Lake is very good street parking is a problem on weekend sunny days.
Alki Beach West Seattle
Alki is our Lido di Venezia throughout the history of Seattle this has been a destination for fun in the sun. Bus service is very good including free bus service up to West Seattle and the Water Taxi back to Seattle. Parking is limited so plan on walking a long ways or taking the bus. I lived on Alki for a few years and always laughed when the police cleared everyone off the beach at 10:00 PM and on some nights there would be sirens, flashing lights and bull horns all trying to clear off the beach some fun loving youth. Also somewhat comical is the strict enforcement of a “cruising” ordinance which limits how often you can drive up and down street along Alki. Early evening until 10:00 PM Alki is just one big promenade of people walking, bicycling, skateboarding, rollerblading and cruising in cars, motorcycles which are all pimped out, expensive or vintage. It gets steamy on a hot summer night and should be on your list of things to experience.
Jetty is not technically in Seattle but is an easy drive and is a day trip. My experience with Jetty was as a Kiteboarder but hundreds of people head to Jetty on any sunny weekend. The fun part is the ferry ride over arrive early because there are a limited number of free tickets. Take everything you will need there are no concession stands on the island it is very rustic but that is what makes it fun.