Welcome Fall 2014….And is it weather or climate?

Weather Blog by Rick Di Maio              Welcome to FALL 2014!

The Equinox Arrived Monday!

Is it Weather or Climate?

Often times, people might say that the snowstorm in the Rockies does not makes sense since they heard the winter was going to be warmer and drier than normal.   While day-to-day observations cannot be argued, it is improper to insert these into a trend forecast for the remainder of a season.   Weather is basically short-term, atmospheric conditions relating to actual temperature, humidity, wind, cloud cover, and precipitation. Climate is longer term that expresses these conditions in averages and extremes and discusses possible reasons for medium and longer-range trends.

This summer was indeed cooler than average but was not a record breaker. It was certainly wet and as a result quite humid at times. For the average person trying to enjoy the outdoors in late May and much of June, we had to deal with many days of unusually heavy rainfall and ultimately an infestation of mosquitoes. What many people tend to forget is that the lack of intense heat led to many days of comfortable temperatures and a decreased need for air conditioning.

The question most people have is how our summer compared to other parts of the country. On a broader note, climate scientists try to examine longer-term trends for the rest of the Northern Hemisphere and the entire Earth for that matter.

Let’s first examine the summer for the Chicagoland area including Rockford:

Lack of heat in 2014… With the calendar now in the latter half of September…the 90 degree mark becomes exceedingly rare with each passing day across northern Illinois and northwest Indiana.

The latest 90 degree reading observed on record in Chicago is October 6 1963 and in Rockford is October 9 2010. while the forecast does call for above normal temperatures for the period September 23 – October 1st, 90s look to be out of reach…meaning these likely could be done for the year.

Here is a look at facts regarding 90 degree plus days so far in 2014:

There have been three days at or above 90 degrees. This is only the tenth time since 1872 /143 years/ of three or less 90 degree   days in a year. the least amount was none in 1875. This is the fewest number of 90 degree days since 2004 which also saw three days.

This was the first august with no 90s since 1986. July 22nd was the last 90 degree day. If indeed that was the final 90 degree reading. This was the earliest end to 90s since July 18 1981.

The 30-year normal number of 90 degree days is 17 days. As for the average temperature so far this calendar year, through September 16th it has been 49.8 degrees. Compared to other years through the mid-point of September. This ranks as the 17th coolest year-to-date since 1872. This also is the coolest year-to-date since 1982.


Stay tuned each Monday for an update on current weather events and the latest up to date outlook for the upcoming winter season. Next week, I will discuss how this past spring and summer will impact the Fall Foliage Season in the Midwest.

Rick DiMaio

Dept of Aviation/Physics/SPCE



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