Today's Onjuku sea temperature is 20.9 °C
(1.3°C colder than average for this time of year)
| Mean: | 22.2 °C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Range: | 20.3 °C to 23.8 °C | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Statistics for 09 Jun (1981–2005) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Today, many surfers would wear a shorty .
Warm in and out of the water temperature at Onjuku today, but forecast to be overcast. With sea temperatures of 20 °C and a wind chill of 20 °C, most surfers will choose a shorty or a summer suit or just board shorts.
 Map of current Japan Surface Water Temperatures (based on measurements from oceanographic satellites) |  Map of current Japan Sea Water Temperature Anomalies (compared with long term averages at this time of year) |
click thumbnails to expand
Below is a graph of Historical Sea Surface Temperature for Onjuku. This has been derived from analysis of two decades of oceanographic satellite measurements of nearby open water. We have calculated the average water temperature variation around the year as well as the extremes that have been observed on each date.
All of the graphs for the surf breaks presented on Surf-Forecast.com are on the same scale to enable comparison between locations around the world.
Onjuku sea water temperatures peak in the range 25 to 28°C (77 to 82°F) on around the 12th of August and are at their minimum on about the 1st of March, in the range 15 to 17°C (59 to 63°F). Year round warm sea water temperatures at Onjuku climb to their warmest in the second week of August. Even then a rash vest and board shorts should be fine for surfing at any time of year. The minimum seasonal sea water temperatures at Onjuku at the beginning of March lend themselves to a 4/3mm wetsuit or a 3/2mm suit and 3mm neoprene boots.
Actual sea surface water temperatures close to shore at Onjuku can vary by several degrees compared with these open water averages. This is especially true after heavy rain, close to river mouths or after long periods of strong offshore winds. Offshore winds cause colder deep water to replace surface water that has been warmed by the sun. Air temperature, wind-chill and sunshine should also be considered before deciding on the kind of wetsuit needed to stay warm when surfing at Onjuku. Refer to our detailed weather forecasts for this information.
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