This Sunday, March 1st, is the beginning of Meteorological Spring, the 3 month period of March, April and May. It’s also the season that we typically see the greatest changes occur in our weather. From snowstorms to warmth, chills to heat, there can be some large swings with the weather during that time.
However, as our climate continues to warm the seasons are also showing signs of warming. A slow and steady climb in Spring average temperatures have been noted since the 1970s in Rockford, with an overall warming trend of a little over two degrees. While noticeably cooler periods have been observed over the last 50 years, there has also been a noticeable warming trend. The Winter season is actually the fastest warming season not only for Rockford and northern Illinois, but also for much of the country. The warming during the 3 month Spring season means there are about 10 more days where temperatures are above average since the 1970s.
The impact of the warming Spring season also means that the Spring last freeze is occurring earlier and earlier in the season. On average, northern Illinois’s last Spring freeze occurs within the last week to week and a half of April. It’s occurred as early as April 7th in Rockford, and as last as May 27th. The last Spring freeze is a good marker for the beginning of the growing season. According to analysis done by Climate Central of 195 cities, 80% of those cities across the United States showed a shift in the last freeze occurring more than a week earlier than it did nearly 50 years ago.
More days above freezing may also mean the allergy season is shifting as well, beginning earlier and ending later than what it has before in the past. Warmer days also mean warm seasonal pests, such as mosquitoes and ticks, are present for longer periods of times. Bird migration, hibernation and even blooming flowers can all be affected by a warming climate.
A warmer environment also means the atmosphere is able to hold more moisture, leading to more precipitation.. For every one degree the atmosphere warms, it is able to hold 4 percent more water vapor. This means that the atmosphere is being given the ‘potential’ for more heavy rain producing storms. Average monthly rainfall towards the latter half of Spring and beginning of Summer generally increases, with June being our wettest month (on average) in Rockford. The increasing rainfall, especially during the growing or harvest season, can have detrimental effects on farmers and on natural resources.
It’s important to understand how greenhouse gas emissions are impacting our climate, where those emissions are mostly coming from and what we can do to help lower those emissions. As the climate continues to change, our seasons will continue be altered and this could have significant impacts on all of us.