Knowing the Land and Sea Breezes

When sailing close to the coast it often seems that NOAA’s wind forecasts are maddeningly inaccurate. How could NOAA get it so wrong?
Author:
Publish date:
prevailingWinds-1

When sailing close to the coast it often seems that NOAA’s wind forecasts are maddeningly inaccurate. How could NOAA get it so wrong? The answer, of course, is that they didn’t. NOAA’s forecasts refer to prevailing winds, but as sailors we need to account for how the land affects the breeze.

After the sun goes down, the ocean retains heat longer than land. This heat rises, creating a low pressure area that gets filled in by the cooler air over the land. The flow of air from the land to the ocean creates a land breeze. Conversely, as the sun rises and heats up the land (the temperature of which changes more drastically between night and day), the low pressure area created by rising warm air is now over the land. The resulting flow of air from the sea to the land creates what is called a sea breeze.

The regular circulation of wind on and off the coast can override the prevailing wind

The regular circulation of wind on and off the coast can override the prevailing wind

No matter what direction it’s from, when the prevailing wind is light, a land or sea breeze can counteract it. Even in stronger prevailing winds, a land or sea breeze can have a noticeable effect. If, for example, you are on the eastern shore of any large land mass and there is an east wind, it will be augmented by the sea breeze during the day. At night, however, it will be decreased, or perhaps entirely counteracted, by the land breeze blowing against it. Conversely, a west wind will be augmented by a land breeze at night, but counteracted by the sea breeze during the day.

In less simplified situations, the land and sea breeze will have different effects depending on local geography. Learning how they behave in your cruising ground will help you make more informed decisions when you study weather forecasts.

Related

MHS-GMR_3549

New Multihulls 2018

Farrier F-22 New Zealander Ian Farrier ushered in a new genre of sailing with his folding-ama trailerable trimarans, the best-known of which are the Corsair designs. Farrier’s last project before he passed away last year was this sweet little tri. Available in three versions, ...read more

shutterstock_373701682

Cruising: Island Comeback

The U.S. Virgins Islands have surged back from the devastation of the 2017 hurricanes, with new infrastructure plans that will benefit charterers and cruisers alike. After hurricanes Irma and Maria roared through the Leeward Islands in September 2017, it was impossible to ...read more

albintoilet

Gear: Albin Pump Marine Toilet

Head Start Is there room for a new marine toilet? Albin Pump Marine thinks so, having just introduced its line of Swedish-built heads—ranging from compact to full-size models—to the American market. The toilets feature vitreous porcelain bowls and either wooden or thermoplastic ...read more

07n_45R2699

Multihull Sailor: Classic Cats

If you’re looking for a decent sub-40ft cruising cat, you have few choices when it comes to new-boat offerings. It is a well-known fact that the multihull market has taken off in a way very few could have predicted. Despite Hurricane Irma’s recent destruction of a large part of ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com Thanks a bunch  This scene is very calm and seamanlike. No frantic rope throwing or shouting. As he passes the line to the gent on the dock, the crew on the boat says, quietly and clearly, “Would you ...read more

mcarthy-and-mouse

Experience: McCarthy and the Mouse

Sitting at the helm in a light breeze, my arms crusted with a fine rime of salt, my skin so dry I’d lost my fingerprints, I heard a clatter and a curse from below. There were only three of us a thousand miles from shore and only one on watch at a time. Usually, the off watch lay ...read more