It's frustrating when it gets cold suddenly for a few days then goes right back to warm and sunny. We've had a very abrupt change from summer to winter.
Here, as long as the ground is still warm, just covering with frost cloth, sheets or blankets keeps the brugs growing and blooming for a couple more months. There's enough heat radiating up from the warm ground to keep the plants warm. If it gets cold in Feb. or March it's a different story, though.