@Rockhead,
When it rains...yes
When I was running a framing crew I would draw a "rain turtle" and tell the guys"ten drops in five seconds and we wrap it up"
But cold? nah
I remember one time I was forming concrete on the 27th story of a high-rise in Wash DC and the temperature was wind-chill -15 and OSHA showed up, did an inspection and said "Carry on"
It's all a matter of where you are geographically