Ask the MB: When Should I Retire the Tweed?
A: While the Farmer's Almanac's frost guide is perfect for the introduction of tweed, it's of no use for its retirement. The average last frost in Green Bay, Wisconsin is May 6, which is way, way too late to be wearing tweed. By then we're in white pants, drinking clear liquor.
Just before Easter might work if it had a set date like Christmas, but the range for this holiday 34 days, which is fine for Jesus's resurrection but unhelpful as a style guidepost.
Rather than rely on Mother Nature or Christian holidays for tweed mothbolling, we've been lead instead by the Energy Policy Act of 2005, which extended the start of daylight savings time (DST) three weeks, to the second Sunday in March starting in 2007. For the past six years we've found the start of DST to be a very reliable and natural-feeling tweed end date.
Earlier: Ask the MB: When to Break Out the Tweed