Climate Watch

By Rick Thoman Alaska Climate Specialist Alaska Center for Climate Assessment and Policy University of Alaska Fairbanks June average sea surface temperatures were generally near to above the 30-year average in nearly the entire Bering Sea and southern Chukchi Sea. The only exceptions were areas where sea ice persisted the longest, in the western Gulf of Anadyr and a small patch north of eastern St. Lawrence Island. However, compared to last year, almost everywhere had cooler ocean temperatures and in many areas it was cooler by a lot.

Around the Seward Peninsula and northward into the Chukchi Sea the June water temperatures were six to as much as ten degrees Fahrenheit cooler than in June 2019. From the Yukon Delta southward, water temperatures were generally two to six degrees Fahrenheit lower than last year, though in a band from Hooper Bay northward and in upper Bristol Bay it was quite similar to 2019.

The only areas with ocean surface temperatures warmer than 2019 were off the Russian coasts.

We need not look far to see why water temperatures were cooler. Sea ice this year in the northern Bering Sea persisted two to six weeks longer than in spring 2019. That’s a critical time for summer ocean temperatures: When ice is present, more of the sun’s warmth goes to melting the ice and less into heating the water. With the ice gone now, currents, winds and the air temperature will shape how temperatures change the remainder of summer and into the autumn.