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September 03, 2008

"Onshore" & "Offshore" Wind


Q:  From what direction does an "onshore" and "offshore" wind blow?

A:  Winds are designated by the area from which they originate.  A sea-breeze originates over the ocean and blows onshore to land.  The opposite is true for a land-breeze.  It originates over the land and blows offshore to the ocean.  In order to minimize confusion, you will hear us use onshore and offshore.

Take care,



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Your definition of on shore off shore winds makes no sense. If winds are designated by where they originate then off shore would be anocean breeze as it originates off shore?????????

Sea breeze and land breeze confuse many. "Does a sea breeze blow to the sea or from the sea?" This is usually the question.

Winds are categorized by where they originate not by where they are going. A sea breeze develops over the sea/ocean and blows onshore. A land breeze develops over land and blows offshore. Another example: A northwest wind would originate northwest of you and blow southeast towards you.

Hope this clears the confusion.



You wrote that the Sun is "straight up" on a couple of dates, Dec 3,4 and Sep 27,28, 29. What do you mean by "straight up"? At the zenith? It will never be at the zenith at our latitude.

Solar Noon is the time when the sun is highest in the sky. In San Jose this occurs at noon on Dec. 8 and 9 when the sun is nearly 30 degrees from the horizon. During Daylight Saving, this happens at 1pm on Sept. 21, 22, and 23 when the sun is 52 - 53 degrees from the horizon.

The sun is never directly overhead, 90 degrees from the horizon. The highest is 76.1 degrees June 16 - 24 and lowest is 29.3 degrees Dec. 16 - 25.

I reat a previous question: Your definition of on shore off shore winds makes no sense. If winds are designated by where they originate then off shore winds would originate off shore and blow towards the shore ?????????

Why is ONSHORE and OFFSHORE so confusing? Winds are USUALLY designated by the direction of origination - this is not the case with ONSHORE or OFFSHORE. Furthermore - a wind blowing from the sea onto the land is named an onshore wind. A wind blowing to the sea from the land is named off shore wind. This is the opposite of the common names of winds; for instance, a wind blowing from the west to the east is named a west wind. In a typical California shore location, where the shoreline runs north-south, a west wind could also be named an onshore wind.

Whoever would think a sea breeze comes from the land? Likewise, nobody would expect a cold, northwind to come from the south. It seems perverse to use the terms "onshore" and "offshore" which, contrary to convention, refer to the direction they are going rather than from where they are coming.

Yeah, I don't get it either. Offshore means off of the shore, so an offshore wind I understand; it blows from the shore. Onshore literally makes no sense, as onshore means on the shore, yet you say this wind blows (originates) from the ocean. Wouldn't a better name be on-ocean?

What is the difference between an offshore and an onshore oil field?

About 10 million dollars, Ananya.

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