Weather Trends-Impacts on Gardeners

​Dr. Mark Seeley, former Extension Climatologist and Professor Emeritus at the University of Minnesota provided statistics and information at the recent Upper Midwest Regional Master Gardener Conference.  The data he presented was based on the same data provided by a UW-Madison online course titled Changing Weather and Climate in the Great Lakes Region where Professor Steve Ackerman showed statistics that may be of interest to gardeners in the Great Lake region.    The list that follows is just some of the trends that you may want to think about as you plan your gardens.  

• The upper Great Lakes region has experienced an increase on average of about 9 additional days in the growing season (the days between the first and last frost) over the last 50 years.  This could mean that we can grow additional and different varieties of plants.  It also means that certain invasive species, insects and diseases may gain a foothold in our area that we have not experienced before.           
• Precipitation levels over the last century have increased 5-10% especially in northern Wisconsin and northern Minnesota.  And we receive that precipitation increasingly in fewer heavy events.  At least 40% of our precipitation falls in 10 or fewer events.   We can make these events less damaging by installing rain gardens that help absorb the excess moisture and installing rain barrels that store the water to be used later. 
• While our overall precipitation levels have increased; spring rains in northern Wisconsin are trending dryer.  This means that we may need to think about irrigation or alternative crops and plants that can tolerant dry spells. 
• Our summer days of extreme heat (defined as over 90°) has a very slight downward trend in the Upper Great Lakes region; however the number of nights with the minimum temperature above 70° is trending higher.  This could help us grow plants that like the heat (think peppers and eggplants). 
• While our springs are getting dryer, our falls are getting warmer and wetter.  Comparing weather data between the 30 year periods of 1951-80 and 1981-2010 the mean temperature has increased by 1 degree and precipitation has increased by 10-30% in the upper Great Lakes. 

 
More information is available at the Midwestern Regional Climate Center.  Another resource is the Wisconsin Initiative on Climate Change (WICC) website for information on climate change specific to our state.   The WICC is a network of many groups and individuals (UW and Wisconsin State agency scientists), who work together to look for ways Wisconsin can mitigate climate change and how we can adapt to those changes.  This is how the WICC summarizes Wisconsin’s climate changes: 
  

• Wisconsin's climate has changed since 1950. The average temperature for the whole state has risen by roughly 1.0–1.5 deg. F. The rise has been uneven: northwestern parts of Wisconsin have warmed by roughly 2.0 deg. F; southern and northeastern parts have not warmed much, if at all. Temperature changes also differ by season. Winter and spring have warmed more than summer and fall. Nighttime low temperatures have risen more than have daytime highs.
• These changes are reflected in Wisconsin's growing seasons. Since 1950, the growing season has become between one and four weeks longer in different parts of Wisconsin. North central and far northwestern regions have seen the greatest growing season increases. Winter has become correspondingly shorter. Lakes freeze later and thaw earlier on average now than they did in the past. These changes are reflected in plant and animal communities. Spring birds arrive earlier today than in the past. Spring plants bloom earlier. Gardeners are seeing shifts in plant hardiness zones.
• We still have weather in Wisconsin, of course. Temperature, precipitation, and storms vary noticeably from year-to-year and day-to-day.  WICCI does not predict the weather. But participants in WICCI are working hard to understand how climate has already changed and how it may change in the future.​

​By sharing this specific data-driven information we can help limit vulnerability to climate change in Wisconsin and the Upper Midwest.