Cold winter weather is a staple of Wisconsin life in a state characterized by its winter sights and activities. Yet, in past years, Wisconsin has experienced unusually warm winters. Surprisingly, the winter of 2023-2024 was Wisconsin’s warmest on record.
Weather experts have identified a strong El Niño pattern as a main factor for the record-setting Winter warmth of the 2023-2024 season. El Niño is the warm phase of the climate pattern of the El Niño-Southern Oscillation (ENSO) cycle. During this phase, sea surface temperatures of the Pacific Ocean warm to above-average, causing the northern part of the United States to experience wetter and milder winter weather conditions.
On the other hand, during La Niña, the cold phase of the ENSO cycle, sea surface temperatures of the Pacific Ocean cool, causing the northern part of the United States to experience colder and stormier weather conditions. Currently, Wisconsin is experiencing a weak El Niña pattern. As a result, the winter of 2024-2025 is expected to act unpredictably, consisting of both extreme cold and average temperatures.
Yet, Wisconsin winter weather conditions are a two-fold experience. According to the Wisconsin Initiative on Climate Change Impacts, Wisconsin will see a significant increase in precipitation in the coming years; in 2041-2060, Wisconsin will see 5% more precipitation than in the past decade. This year, additional moisture from the effects of La Niña may lead to increased precipitation. As a result, Wisconsinites can expect more snow than the previous year: about 30 to 40 inches.
Furthermore, human-influenced climate change has strengthened the phases of the ENSO cycle. Self-reinforcing feedbacks between the ocean and the atmosphere trigger the ENSO cycle and become stronger in a warm environment produced by human greenhouse gas emissions. A warmer environment causes the upper layers of the Pacific Ocean to warm faster than the deeper layers, increasing precipitation. Thus, human greenhouse emissions augment the extremity of the swings between El Niño and La Niña in the ENSO. Consequently, Wisconsin is expected to become one of the states most impacted by warming patterns. Over the past 70 years, Wisconsin’s average low winter temperature has risen from two to four degrees.
So, how can Wisconsinites get through the unpredictable winter climate this year? Bundle up and look forward to the end of a predictable winter season!
