When do upslope winds usually take place?

Upslope winds typically occur in the morning due to the heating of the Earth's surface by the sun. As the sun rises, it warms the ground and surrounding air, causing the air near the surface to become warmer and rise. This creates a pressure gradient that draws in cooler air from the surrounding areas to replace it, resulting in upslope winds that flow up the mountain slopes during the day.

In contrast, during the evening and at night, temperatures generally cool down, and winds may reverse, leading to downslope or valley winds instead. The generation of upslope winds is, therefore, closely tied to the heating patterns of the day, particularly in the morning when sunlight starts to raise the temperature.