12.4: Effect of Continental Position on Climate

Is latitude making the difference in weather in these three cities?

No. These three cities are at the same latitude. They are San Francisco, California; Wichita, Kansas; and Virginia Beach, Virginia. Proximity to the ocean is important. Also important is the direction the winds are blowing at this location.

Oceans and Climate

When a place is near an ocean, the water can have a big effect on the climate.

Coastal and Inland Climates

Places at the same latitude may have very different climates if one is on a coast and one is inland.

• On the coast, the climate is influenced by warm moist air from the ocean. A coastal climate is usually mild. Summers aren’t too hot, and winters aren’t too cold. Precipitation can be high due to the moisture in the air. This is a maritime climate.
• Farther inland, the climate is influenced by cold or hot air from the land. This air may be dry, because it comes from over land. An inland climate is usually more extreme. Winters may be very cold, and summers may be very hot. Precipitation can be low. This is a continental climate.

The Influence of the Ocean

The ocean has a big effect on climate. This is obvious when you compare the temperatures of these three cities. Each of these cities is located at 37°N latitude, within the westerly winds (Figure below).

How does the ocean influence the climate of these three cities?

The climate of San Francisco is influenced by the Pacific Ocean. The cool California current comes from the north. Upwelling brings cold water from the deep. So the water offshore is cold. Virginia Beach is near the Atlantic Ocean. But its temperatures are more like Wichita than San Francisco. Why is the climate in Virginia Beach less influenced by the ocean than San Francisco? Hint: Think about the direction the winds are going at that latitude. The weather in San Francisco comes from over the Pacific Ocean. Much of the weather in Virginia comes from the continent.

Ocean Currents and Climate

Ocean currents carry warm or cold water throughout the world’s oceans. They help to even out the temperatures in the oceans. This also affects the temperature of the atmosphere and the climate around the world. Currents that are near shore have a direct impact on climate. They may make the climate much colder or warmer. Examples of this are pictured below (Figure below).

The Gulf Stream moves warm equatorial water up the western Pacific and into northern Europe. The warm water raises temperatures in the British Isles.

Summary

• A maritime climate is influenced by a nearby ocean. A continental climate is influenced by nearby land.
• The temperature of offshore currents affect nearby land areas.
• A maritime climate is less extreme than a continental climate, because the ocean moderates temperatures.

Review

1. Describe a maritime climate. What location has a maritime climate?
2. Describe a continental climate. What location has a continental climate?
3. San Francisco and Virginia Beach are both near an ocean. Why are their climates so different?