Sometimes in very cold climates locks freeze and will not allow the key to turn the lock. One method to help thaw the lock is to heat the key using a lighter. With your gloves on, heat the key with the lighter for several seconds or until hot. Then place the key into the keyhole and very gently move the key in-and-out and try turning the key. Warning: Do not apply too much pressure turning the key or you could break the key! It may take several tries carefully working the key into the lock before the lock will turn.
TIP: Wear your gloves to protect your hands from getting burned while heating the key and placing the key in the frozen lock. Even after several tries, do not force the key or it may break inside the lock. Be patient. This method may take several minutes before it works.