By Brandon Hoppe
According to former NC State Extension Specialist, Dr. Sara Spayd,
Don’t be tempted to prune after a few beautiful, unseasonably-warm days. Even hedging. Pruning helps to stimulate vine growth. You may see grape buds in some degree of bud swell, particularly the European bunch grape varieties. Those varieties have very little chilling requirement that can be met in a few cold days.
A short cooling pattern will do little to harden the vines and buds for any potential cold weather in January or February. A precipitous drop (30-40°F) in temperatures after warm weather can cause a lot of damage.”
Source : ncsu.edu