Halloween Climate Data for Chicago

Halloween Weather for Northern Illinois: Statistics for Chicago and Rockford

Chicago:
The following statistics comprises 140 years of data. Data collection began at the University of Chicago, then at Midway, and currently at O'Hare which is now the official station for Chicago.

Frequency distribution of high temperatures for Chicago. This dataset shows that the most frequent range of high temperatures on Halloween is in between 50 and 59 degrees. The normal high for Halloween is 56 degrees, which falls in the range of the most frequent highs. The record high is 84 degrees set in 1950. This was the only time in Chicago’s history that the high temperature on Halloween was in the 80s. The coldest high temperature on Halloween is 31 degrees which occurred in 1873.

Frequency distribution of low temperatures for Chicago. This dataset shows that the most frequent range of low temperatures on Halloween is in between 40 and 49 degrees. The normal low for Halloween is 39 degrees, which falls in the range of the second most frequent lows. The record low is 23 which occurred in 1873. The highest low temperature for Halloween was 65 degrees in 1974. In 2011, the low temperature in Chicago was 36.

Frequency distribution of precipitation for Chicago. This dataset shows that the most frequent amount of precipitation recorded on Halloween is 0.00”, which accounts for 51% of the days in the dataset. The next most frequent range is the 0.02” to 0.25”, closely followed by a trace of precipitation. The record amount of rainfall on Halloween occurred in 1994 when 2.26” of rain fell. There have been 2 instances dating back to 1872 where an inch or more of rain fell on Halloween. In 2011, there was no precipitation on Halloween.

There have been five instances in Chicago’s history where snow has fallen on Halloween, but there has never been a measurable amount. The last time that it has snowed on Halloween was in 1993 when a Trace of snow fell.

ADDITIONAL HALLOWEEN CLIMATE DATA ( * MEANS LAST OCCURRENCE)

MAX TEMP WARMEST	MIN TEMP WARMEST	PCPN WETTEST	SNOW
84 1950	65 1974	2.26 1994	T 1993 *
79 1944	61 1900	1.27 1941	0.0 2011 *
78 1935 *	59 1933	0.75 1912
77 1974 *	58 1950 *	0.65 1973
76 1915 *	56 1909	0.62 1935

MAX TEMP COLDEST	MIN TEMP COLDEST	PCPN DRIEST
31 1873	23 1873	0.00 2010 *
32 1917	24 1917	T 2009 *
37 1878	25 1993	0.01 2003 *
39 1930 *	26 1996 *	0.02 1991 *
40 1996 *	27 1913	0.03 1972 *

Updated 10/26/2012 ACS

National Weather Service Weather Forecast Office