The climate of the United States and of the Midwest have changed over time. Below are some of the ways in which those changes have occurred.
Changes in Agriculture
The frost free season is the days between the last freeze in spring and the first freeze in the fall.
This graph shows that in all parts of the US this season is increasing. In the Midwest, the frost free season increased by 9 days over the time period of 1991-2001 compared to 1901-1960.
Changes in Temperature
This graph shows how temperatures have changed from the early 1900s to the 2000s – a 100 year time period. In this graph, the 0 is the average temperature for this 100 year time period. Each bar is the average temperature for each decade.
The blue bars show when the temperature was below average and the red bars show when temperatures were above the overall average temperature.
Since 1980, the temperature has been above average, and it keeps getting warmer each decade.
Changes in Precipitation
This graph shows how the amount of rain (precipitation) has changed from the early 1900s to the 2000s – a 100 year time period. In this graph, the 0 is the overall average amount of precipitation for this 100 year time period.
Each bar shows how much more or less precipitation happened in each decade compared to the 100-year average. The brown bars show when rainfall was below average and the green bars show when rainfall was above average.
Since 1960, we’ve had more rain than average, and the amount of rain keeps increasing each decade since then.