ne'er cast a clout till may be out

The phrase "ne'er cast a clout till may be out" means that one should not remove or discard any warm clothing or protective layers until the month of May is over. In this context, "clout" refers to a piece of clothing or a layer that provides warmth or protection. The advice is generally given to caution against premature abandonment of protective measures as the weather in May can still be unpredictable, fluctuating between cold and warm conditions.