Spending time on Lake Washington along its namesake boulevard is something many residents look forward to doing in the spring and summer. With the warm weather comes Bicycle Weekends, a decades-old summer program of the Parks & Recreation Department in which a stretch of the Lake Washington Boulevard — from Seward Park to Mount Baker Beach — is shut down to vehicles and reserved for pedestrians and bike riders. Over the years, the days and times have changed. Some years it’s been Sundays only; other years, Saturdays and Sundays, from 10 a.m. until 6 p.m. But this year, Mayor Katie Wilson expanded Bicycle Weekends from 10 weekends to 15, and expanded the daily times. Most weekends will see the road closed to vehicles from 7 p.m. Friday until 6 a.m. Monday. And on Memorial Day weekend, the nearly three-mile stretch will close to motorists on Friday at 7 p.m. and will not reopen until Monday night. The same schedule will be in place for the July 4 and Labor Day weekends.…