You don't expect to see 75 or even 80-degree water in the Great Lakes in early July or, in most years, anytime. But an exceptionally hot weather pattern has pushed water temperatures in most of the lakes to the highest levels on record so early in the summer. Over lakes Erie and Ontario, the water is the warmest it has been since the records began, and could warm more in the coming weeks.

The abnormally warm waters, consistent with climate change trends in recent decades, could compromise water quality and harm marine life in some areas.              

Surface water temperatures averaged over all of the Great Lakes, except the deep and choppy Lake Superior, have risen well into the 70s while Lake Erie has flirted with 80 degrees. That's about the same water temperature as the surf off Virginia Beach, Va.

These water temperatures over the lakes are some 6 to 11 degrees warmer than normal.

Here is how warm each of the lakes has become over the past week:

Lake Michigan's average water temperature reached 75.1 degrees on July 8, nearly 11 degrees above normal, and the warmest mark on record so early in the year. The water temperature in July has only been this warm one other time, at the end of the month in 1999.

Lake Huron's average water temperature reached 72.2 degrees on July 9, nearly 11 degrees above normal, and the warmest mark on record so early in the year.

Lake Ontario's average water temperature reached 77.1 degrees on July 10, over 10 degrees above normal, and the warmest mark on record for any month, although it was similarly warm in mid-August 1995.

Lake Erie's average water temperature reached 79.6 degrees on July 10, over 8 degrees above normal, and the warmest mark on record for any month, also similarly warm in mid-August 1995.

Lake Superior average water temperature reached 55.8 degrees on July 8, over 6 degrees above normal.

The unusually warm water is a reflection of blistering heat over the Great Lakes region in recent weeks set up by a persistent ridge of high pressure.

Air temperatures in early July, especially in the eastern Great Lakes, were among the warmest on record.

Buffalo hit at least 90 degrees on eight straight days ending Friday, its longest streak ever observed. Muskegon, Mich., on the shores of Lake Michigan, also notched its longest 90-degree streak, tallying nine straight ending July 7.

Massena, N.Y., about 90 miles north of Lake Ontario in upstate New York, hit 99 degrees Friday, its second highest temperature ever recorded.

The heat has meant water temperatures are "abnormally high compared to the most recent years," said Andrea VanderWoude, manager of the Great Lakes CoastWatch program at the National Oceanic and Atmospheric Administration. "Last year was really cold and there was a lot of rain. This year there hasn't been as much rain and it's been persistently hot."