(COLORADO SPRINGS) — A question that came into my email box last week, and a comment from my wife over the weekend, gave me reason to dig into some historical data regarding fall temperatures in Colorado Springs. They can be used as an approximation for the rest of the region, too. Over the last five-plus decades the average temperature in Colorado Springs, like many areas of the western United States has risen a significant amount. While there is fluctuation on a year-by-year basis over that time (individual years are represented by the burnt sienna line in the top graph), the trend line shows 4.5°F of warming since 1970. Notice that many areas of the western U.S. have warmed between 3°-5°F over the same time. Warming hasn't been as significant over the southeastern U.S. This probably isn't a surprise with the average temperature through fall has increased, but over the same time, the average number of days we spend above average in fall has increased as well.