Winds are usually calmest during which times of day?

Winds are usually calmest during which times of day?

• A. Midday
• B. Early morning and early evening
• C. Night
• D. Afternoon

Answer: (B)

Winds at ground level are driven by how much the day heats the surface. When solar heating is minimal—early morning just after night’s cooling and again as the sun is setting—the lower atmosphere is stable and mixing is weak, so the winds tend to be very light. This is why the calmest periods are typically early morning and early evening. During midday and early afternoon, strong heating creates thermals and more turbulent mixing, which increases wind speeds. Night can also be relatively calm, but the most consistent calm periods described here are the early morning and early evening.

Winds at ground level are driven by how much the day heats the surface. When solar heating is minimal—early morning just after night’s cooling and again as the sun is setting—the lower atmosphere is stable and mixing is weak, so the winds tend to be very light. This is why the calmest periods are typically early morning and early evening. During midday and early afternoon, strong heating creates thermals and more turbulent mixing, which increases wind speeds. Night can also be relatively calm, but the most consistent calm periods described here are the early morning and early evening.