How cold is really cold? I hate being cold, but I don’t mind being outside as long as it is above freezing, as long as I can get into the warn every so offten. Below freezing can be brutal, I would say below 20 and I am pissed off. I would be pissed off all day if I worked in 20 degree weather for many weeks or months in a row. Although, I rather be in snow than a cold rain. Nothing is worse than cold rain.
If you deliver mail by truck or car, you get to be in the car a little protected. If you deliver it walking then the elements can be brutal.
Construction can be cold. Roof repair. Phone, electric, or cable company if you do the work out on the lines.