Why would bees be out flying around in 36 degree weather?

I assume that you mean 36 on the Fahrenheit scale ie, 4 degrees above freezing. This is just about as low as it can get before bees will not leave their hive. On a sunny day, even when the temperature is this low, bees will leave their hive on an 'evacuation' or 'cleansing' flight rather than use the inside of their hive as a toilet.