Climate change leading to shifting seasons and longer summers
SOUTH BEND, Ind.-- Summer may be winding down, but the recent warmth tells a different story. Due to climate change, summer is extending while other seasons are being squeezed. This trend has been apparent in Michiana in recent years.
Historically, our last 80s-degree day falls around Oct. 5. However, in four of the past five years, temperatures have remained warm well beyond that date--2022 being the exception. According to Climate Central, summer temperatures have extended roughly 10 days later into fall since 1970. Additionally, autumn itself has warmed by an average of 2.4° for hundreds to cities across the U.S. Pollution trapping heat near the surface is largely driving this shift.
As a result, summers are getting longer, and winters are being compressed. This is also noticeable in the transition seasons as well—as sometimes it can feel we only receive a few weeks of true spring and fall weather.
Steady warm temperatures contribute to increased seasonal risks. Prolonged above average temperatures breed extended allergy exposure, heat-related illnesses and increased wildfire risks. Other risks include drought/water stress, the prolonged presence of mosquitos and shifts in the fall color timeline. Cooler temperatures help to slow and ease the progression of these risks, allowing them to become dormant; however, the relief is being delayed.
Recently in Michiana, this pattern of warmer air has been evident for several days. Over the past week, highs have rested in the mid to upper 80s-- about 10 degrees above average for the middle of September. Even today, just four days away from the first day of astronomical fall, highs are expected to remain warmer than average.
Looking ahead, the latest 8–14 day temperature outlook from climate models suggests a continuation of above average highs through the end of the month. That likely means highs staying above the low 70s and no signs of below 40° mornings in South Bend.
While the days are getting shorter as we approach astronomical fall, sweater weather could likely be put on the back burner until October.