A daytime frost has ended the growing season for most area plants, data from WeatherUnderground indicates. Depending on your location, the growing season length in 2011 was between 233 and 235 days. The average growing season in Chicago is expected to be between 170 and 175 days, according to the State Meteorologist.
However, pockets of warmer temperatures, buildings and other shelter could lengthen the growing season still, as not all stations have reported frost.
In the Ravenswood neighborhood, the frost can be measured through five weather stations that post logs of weather.
- Irving Park Kilchica69 reported the temperatures hit 32° F at 2A and didn’t rise above freezing till 10.54A, with winds below gusting as high as 13 mph, but generally under 5 mph, the frost here was nearly 9 hours long. The thermometer went back down to 32° F at 9.15P, staying cool until 1.32A this morning.
- Lincoln Square Kilchica105 reports temperatures hit freezing at 2.41A yesterday and remained in the freeze range till 8.32A yesterday. The station did not report a frost last night.
- North Park Kilchica58 reports temperatures rose above freezing at 12.30A, a three hour frost that started at 9.30P Thursday, after a first frost lasting from 2.30A to 10.30A Thursday.
- Kirzanadu, located in Lakeview, Kilchica63, reports no frost yet. If you live by the lake, the growing season continues!
- Just a few blocks away, however, Wrigleyville Kilchica60, reports frost hit at 2.46A Thursday and didn’t lift till 10.46A. Weather is very localized.
With the first frost out of the way (except for Lakeview), we can consider the first measurable snowfall. (Did you notice the freezing rain earlier in the month? It was rated as our first snowfall of the season, according to weather guru Tom Skilling.)
According to the National Weather Service the earliest snowfall in a season hit Chicago on September 25, 1928 with the earliest measurable snowfall happening on October 12, 1909.
When do you think the first measureable snow fall will happen in the hood? Last year it happened on December 1.
Tom Skilling talks about frost.
Tom Skilling on the first snowfall of 2011.
Learn more: Illinois state climatologist Jim Angel, PhD defines a frost.
Learn more: Illinois state climatologist Jim Angel, PhD discusses the growing season.
Learn more: Illinois State Water Survey updated frost dates.
