Climatology — Belt of the Tropical Easterlies (Trade Winds) At approximately which latitude band do the tropical easterlies, commonly called the trade winds, predominate in each hemisphere?

Introduction / Context:
The global atmospheric circulation creates three major wind belts in each hemisphere: the tropical easterlies (trade winds), the mid-latitude westerlies, and the polar easterlies. Knowing their typical latitudinal ranges is basic climatology that supports understanding of ocean currents, rainfall belts, and navigation routes.

Given Data / Assumptions:

• Tropical easterlies are the surface manifestation of the Hadley cell return flow.
• We need the approximate latitude range where these winds are most persistent.
• Idealized ranges may shift seasonally but remain broadly consistent.

Concept / Approach:
Because of the Hadley circulation, air descends in the subtropics near 30° and flows equatorward at the surface. The Coriolis effect deflects this flow to the west, producing easterly winds (from the east) between the Intertropical Convergence Zone near the equator and the subtropical highs. Hence the classic band is about 0–30° in each hemisphere.

Step-by-Step Solution:

Verification / Alternative check:
Climatology diagrams of global wind belts label the trades as 0–30°, the westerlies as 30–60°, and the polar easterlies as 60–90°.

Why Other Options Are Wrong:

• 30–60°: This is the mid-latitude westerlies.
• 60–90°: Polar easterlies, not tropical trades.
• 10–40°: Overlaps but is not the standard belt; excludes equatorial trades and includes part of the westerlies.

Common Pitfalls:
Forgetting that the trades extend to the equator (seasonally shifting ITCZ), not starting at 10°.

Final Answer:
0–30° latitude