Average Ocean Temperatures for Oregon

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Average ocean temperatures for each month along the Oregon coast are listed below in degrees Fahrenheit and degrees Celsius.

You'd expect sea temperatures to grow cooler as you head north along Oregon's shore. But that is true only in winter and spring. From May to November, the southernmost site measured, Port Orford, has the coldest water.

Local conditions create the strange pattern. Inlets, bays and rivers influence the ocean's temperature along Oregon.

The water temperature at Port Orford is measured in the open sea. But to the north, temperatures are taken in inlets where the sheltered water gains a little warmth. The ocean at Charleston, near Coos Bay is monitored in a bay near the entrance to an inlet. The water at Newport is measured in Yaquina Bay, east of highway 101, near the Hatfield Marine Science Center.

Seaside in northern Oregon has the warmest ocean of all the places measured on the Oregon coast during summer, despite temperature readings taken there in exposed water. The unusually high temperature is due to the influence of the Columbia River, which empties into the ocean a short distance to the north.

Just around the corner, along the river mouth at Astoria, the water in summer gets even warmer. The river temperature near Astoria peaks at 68 °F (20 °C) in early August, many degrees higher than the ocean.

Only the hardiest will want to stick more than their bare toe in the ocean off any Pacific beach in Oregon. The water throughout the year stays too cold for swimming without a wetsuit.

Average ocean temperature in °F
  Port Orford Charleston Newport Seaside
January 50 50 49 49
February 50 50 50 49
March 50 51 50 50
April 50 52 50 51
May 51 53 52 54
June 51 55 55 58
July 51 55 55 58
August 52 55 55 58
September 53 55 56 58
October 52 53 54 55
November 52 53 53 53
December 51 50 52 51
Annual 51 53 53 54
Water temperature averages in °C
  Port Orford Charleston Newport Seaside
January 10 10   9   9
February 10 10 10   9
March 10 11 10 10
April 10 11 10 11
May 10 11 11 12
June 11 13 13 14
July 11 13 13 14
August 11 13 13 14
September 12 13 13 14
October 11 12 12 13
November 11 12 12 12
December 11 10 11 11
Annual 11 11 11 12

These coastal water temperatures are averages compiled by the National Oceanographic Data Center. Actual ocean temperatures do vary from year to year depending upon the weather and the flow of ocean currents.

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