Sounds very similar to my climate. I would have started my car in the low to mid-50's F this morning, it wasn't a problem. The overnight low was about 45F. Still it's your car and your decision.The coldest temp I experienced this winter was 38-degrees F. There were only 2 or 3 days like that. Generally the coldest temps were around mid-40s, but low to mid-50s was more common.
Hey, right now it's summer over there anyway ...