For the most part, the winter season was downright balmy, with only one small stretch of negative temperatures in January, making it the warmest on record for Wisconsin, said Steve Vavrus, Wisconsin’s state climatologist and the assistant director at the University of Wisconsin Madison’s Center for Climatic Research. The El Nino effect — which carries warm air from the central and eastern tropical Pacific Ocean across the U.S. — is largely to blame for the warmth.
“It was a full two degrees warmer than the previous record, which is a huge amount,” he said. “We had the warmest December on record. We had the warmest February on record and we had the 10th warmest January on record. So that really is extreme in terms of consistent warmth over a whole season.”