Prevailing Winds in Tokyo: The Westerlies and Their Impact

Tokyo, situated in the mid-latitudes of the Northern Hemisphere, lies squarely within the prevailing westerly wind belt. These winds blow from west to east, driven by the global atmospheric circulation pattern known as the Ferrel cell.

Seasonal Influence

• Winter: Cold, dry northwesterly winds (the "northwest monsoon") dominate, bringing clear skies and frigid temperatures from Siberia.
• Summer: The westerlies shift north, allowing the subtropical high to bring hot, humid southerly winds. This is also when the typhoon season peaks (August–September), as tropical cyclones track along the western edge of the Pacific High.

Weather and Climate Effects

The westerlies transport moisture from the Sea of Japan, contributing to Tokyo's significant winter snowfall on the Sea of Japan side (though Tokyo itself gets less snow). They also steer weather systems eastward, meaning storms typically approach from the west or southwest.

Typhoon Connection

While the westerlies don't create typhoons, they influence their tracks. As typhoons move north, they often get caught in the westerly flow, accelerating them northeastward toward or past Japan.