50's is nothing as it's the norm year-round for night time temperature in SF. Thermal layer for ~15mins and I'm good to go on shorts and shirt.
However, I have played a few times when the temperature got into the lower 40's. Same story, but the colder it gets, I find it to be more and more tiring. I wonder if it's because the body is spending extra energy to keep metabolism going in colder temperatures.