Has this spring felt a little chillier than normal? If it has, then that would be a pretty good observation. Indiana’s 2026 spring has seen average temperatures around 12 degrees lower than the normal.
Part of the reason for the low temperatures has been the surface temperature of the Pacific Ocean, which may sound silly, but those temperatures are directly related to the behavior of the jet stream. If temperatures in the central Pacific are high, an El Niño occurs, and the jet stream’s path dips into the dry Mojave desert as it moves into the Midwest. This usually brings dry heat, and can sometimes cause a drought.
On the contrary, when Pacific surface temperatures are low, a La Niña forms, which causes the jet to push up into the cold and wet Pacific northeast on its way over to Indiana. This pattern brings frequent cold fronts and sometimes even storms.
The reason the weather has been so weird and unpredictable is due to the fact that the Pacific has been in what meteorologists have been calling a “weak ENSO-neutral” state since late 2025. This means that temperatures have been average so neither an El Niño or La Niña has formed, but there have been some fluctuations in the jet stream, particularly in the northern polar vortex, that have been causing minor disruptions in weather patterns.
Understanding the behavior of the pacific and this weak ENSO-neutral state is key in understanding why Indiana has seen lower temperatures and unpredictable rain patterns this spring.
