Julia Poska | October 30, 2019

Iowans across much of the state awoke Tuesday morning to find a blanket of fresh snow atop vibrant orange and yellow autumn leaves, many still attached to the trees. Parts of east and east central Iowa saw as much as three to four inches, according to the Des Moines Register. 

The National Weather Service  puts eastern Iowa’s average date of first one-inch snowfall in early December.  The unseasonable flurry might have some Iowans questioning how serious Midwestern climate change–characterized by increasing average temperatures– could really be.

But climate (average temperature and precipitation over several decades) is not the same as weather (daily atmospheric conditions). Years of abnormally high snowfall or abnormally cold weather could impact climate averages over time, but singular snow and frost events are products of normal weather variation throughout the year.

Records show that overall, average annual temperatures in Iowa and most of the world are increasing, despite weather variation. This pushes local 30-year climate averages (shown below for Iowa City) up by small increments over time.

Iowans can still expect snow and cold in coming decades, though the overall frequency and intensity of such events may decline over time. Somewhat milder winters will be followed by much hotter, dryer summers, with an increased number of intense rainstorms added to the mix.