If you work inside a building or office then the office or building must be maintained at a certain temperature.
That temperature is usually 60 F that the office or building must be maintained at and can't fall below that temperature but it can go above that temperature.
For outdoor workers there's no law about being too cold of conditions or too hot of conditions to work in.
But some places do shut down outside work when it gets below a certain temperature that is dangerous such as below zero or if it's too hot above 100 F.
There's no OSHA law that says the employer must shut down during below freezing temperatures or above 100 F.