CHAMPAIGN — You can tell your grandkids you were there for the earliest 80-degree day in Champaign-Urbana weather history.

The temperature at the Illinois State Water Survey reached 81 degrees around 3 p.m. Wednesday, not only breaking the record high for March 14 (which was 78 degrees, set in 2007) but also the soonest in the calendar that the temperature eclipsed 80 degrees.

The earliest previous reading was March 21, 1907, when it was 85 degrees. Champaign-Urbana temperature records go back to August 1888.

"This is highly unusual weather," said Chuck Schaffer, a meteorologist at the National Weather Service in Lincoln.

Remember, astronomically speaking, it's still winter.

And temperatures have been above average for months.

"To put it simply, the main jet stream has been located across Canada for much of the winter," he said, "so that kept all the cold air bottled up to our north. So we're getting air masses in off the Pacific Ocean that moved across the country, and occasionally air masses from the southwest U.S. would come up here. That's really what gave us the warm winter, the lack of arctic air to come this far south."

The pattern also has meant colder-than-average temperatures in Europe, Asia and Alaska, he said.

"It's just a pattern that has been in place for many months and hasn't changed much," Schaffer said.

The current wave of warmth — three consecutive days of 70-plus temperatures with more to come — is the result of sustained south to southwest air flow, he said.

"Usually we'll have a day or two in early to mid-March where it will get into the 70s. But to have it for the last several days and for several days to come, that's highly unusual," Schaffer said. "The south to southwest flow is at all levels of the atmosphere, not just at the surface. There's nothing in place to stop it. And it's been sunny too. That also helps heat up the lower atmosphere as well."

The warm wave — with temperatures 25 to 30 degrees above normal — is expected to continue at least to next Wednesday, according to the weather service, with highs each day in the mid- to upper 70s.

"There may be a change in the upper air pattern later next week, but up until that point it looks like we'll be in the same pattern," Schaffer said.

In addition to the record warmth in Champaign-Urbana, new highs were established Wednesday in Springfield, Peoria, Lincoln and Bloomington.