November 3: ORD

Today is November 3rd. It's the 308th day of the year. 58 days remain. It's week 44 of the year.  
 
Unless noted, the following data is based upon observations collected by the National Weather Service, Chicago, at O'Hare International Airport (ORD) between November 1978 and last year. ORD has been the official site of record for Chicago since Thursday, January 17, 1980. Before this, the official site was on the south side of Chicago at Midway International Airport (MDW), beginning on Wednesday, July 1, 1942. From Friday, January 1, 1926 through Tuesday, June 30, 1942, the official site was at the University of Chicago. Before that, the official site was at various locations in Chicago going back to Monday, October 16, 1871. Observations taken from October 15, 1870 to October 8, 1871 were lost in the Great Chicago Fire.
 
According to the National Climatic Data Center (NCDC), the normal high is 55 and the normal low is 38. I've calculated the 34-year averages at 53 and 36.

On the warm side, in 1987 (O'Hare's warmest November 3rd) the high was the record high of 75 with a low of 57 (O'Hare's third warmest low of the date). The record high of 75 also occurred in 1938 and 1964. In 2008 the high was 73 with a low of 54. Three years earlier, in 2005, the high was 70 with a low of 53. In 1994 the high was 68 with a low of 54. In 1978 the high was 74 (with 1964, O'Hare' second warmest high of the date) with a low of 43, a 31 degree spread. In 1990 the high was 70 with a low of 47. A decade earlier, in 1980, the high was 66 with a low of 50. The other warm high is 68 degrees in 1981. The record warmest low of 60 degrees occurred in 1975 at Midway. 22 of the past 34 highs (65%) were in the: 40s (14) and 50s (8). Ten highs (29%) were in the warm: 60s (5) and 70s (5). Our most recent 60s high was 66 degrees in 2001. Two highs (6%) were in the cold: 20s (1) and 30s (1). O'Hare's second warmest November 3rd days were in: 1975 (high of 67, low of 62 (O'Hare's warmest low of the date)) and 1977 (high of 71, low of 58 (O'Hare's second warmest low of the date)). O'Hare's other warm days were in: 1964 (high of 74 (O'Hare's second warmest high with 1978), low of 51)) and 1965 (high of 73, low of 50).    

In looking back through the years to the first November at O'Hare in 1958, the following instances were notable: in 1977 the high was 71 with a low of 58, a warm day. In 1975 the high was 67 with a low of 62, a five degree spread, warm day and year of the record warmest low of 60 at Midway. In 1972 the high was 46 with a low of 41, a five degree spread. In 1969 the high was 44 with a low of 41, a three degree spread. In 1967 the high was a cold 41 degrees. In 1966 the high was 36 with a low of 23, a cold day. In 1965 the high was 73 with a low of 50, a warm day. In 1964 the high was 74 with a low of 51, a warm day. In 1963 the high was 59 with a cold low of 21, a 38 degree spread.

More recently, there was an additional large spread of 31 degrees in 2001 (66/35). There were additional small spreads of two degrees last year, in 2011 (48/46), five degrees in 2003 (51/46) and seven degrees in 1997 (40/33).

On the cool side, in 1991 (O'Hare's coolest November 3rd) the high was the record coolest high of 24 (O'Hare's only 20s high of the date) with a low of 13 (O'Hare's coldest low of the date and only 10s (a.k.a. teens)) low. Four years later, in 1995, the high was 33 (O'Hare's second coolest high of the date) with a low of 27, a six degree spread. In 2006 the high was 40 with a low of 21 (with 1963, O'Hare's third coldest low of the date). In 1989 the high was 41 with a low of 20 (O'Hare's second coldest low of the date). The other cold lows are 21 degrees in 1963 (with 2006, O'Hare's third coldest low of the date), 23 degrees in 1996, 24 degrees in 2002 and 25 degrees in 1984. The other cool highs were 40 degrees in 1997, 41 degrees in 1967 and 42 degrees in 1992. The record low of 11 degrees was set in 1951 at Midway. 22 of the last 34 lows (65%) were in the: 20s (9) and 30s (13). Eight consecutive lows from 1995 through 2002 were in the 20s and 30s. One low (3%) was in the cold 10s (aka teens). 11 lows (32%) were in the warm: 40s (6) and 50s (5). O'Hare's second coolest November 3rd was in 1966 as the high was 36 (O'Hare's third coolest high of the date) with a low of 23.
 
There's been three instances of back-to-back years in which temperatures were just about as opposite as they can be. The first instance was a back-to-back-to-back occurrence: in 1989 the high was 41 with a low of 20, overall 15.5 degrees BELOW normal. Then in 1990 the high was 70 with a low of 47, overall 12.5 degrees ABOVE normal. Then in 1991 the high was 24 with a low of 13, overall 27.5 degrees BELOW normal. In the second instance, in 1994 the high was 68 with a low of 54, overall 15 degrees ABOVE normal. Then in 1995 the high was 33 with a low of 27, overall 16 degrees BELOW normal. Thirdly, in 2005 the high was 70 with a low of 53, overall 15.5 degrees ABOVE normal. Then in 2006 the high was 40 with a low of 21, overall 15.5 degrees BELOW normal.  

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 7:00 and sunrise is at 7:30. Sunset is at 17:44 and twilight ends at 18:13. There's a total of 10 hours, 14 minutes of daylight today and 11 hours, 13 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:01 and sunrise is at 6:31. The moon is waning gibbous. Illumination was 84% at midnight, will be 80% at noon and 76% at midnight tonight. Moonset is at 11:36 this morning. Moonrise is at 21:23 tonight. Moonset is at 11:15 tomorrow morning. Moonlight time is 14 hours, 13 minutes which is eight minutes shorter than yesterday. Moonlight time is near its peak today.

Cool Fall began yesterday, on November 2nd and runs for 29 days through November 30th. High temperatures in this period are usually in the 30s, 40s and 50s. Highs in the 10s and 20s occur infrequently. Standard Time returns tomorrow. Election Day is in three days. Veteran's Day is in eight days.