OK, riding season is really any day the temperature is high enough, but in the northern hemisphere and especially here in the U.S., the Memorial Day weekend is taken as the start of the summer season and riding is in full swing. Temperatures are doing their part with 80s even in the northern states and the roads are absolutely filled with motorcycles. Even those folks who confine their riding to perfect days have little reason to leave the bike idle.
What are you waiting for? Go for a ride. See you tomorrow.