In most cases, window installation can be done in the downpour. In certain extreme circumstances, it is much safer not to. In monsoon conditions, the weather can be extremely hazardous.
Windows can be installed from both the interior and exterior. Typically, however, professional installers will install them from the exterior. It enables the installer to properly seal and weatherproof the frame while minimising mess and property disruption.
When the temperature falls below -20°C, caulking becomes brittle and difficult to apply, so installation is typically impossible. The effect snowfall has on window installation is frequently overlooked by householders.
A glazier is a tradesperson who cuts, installs and removes glass (and materials used as glass substitutes, such as certain polymers).