November 16: ORD

Today is November 16th. It's the 321st day of the year. 45 days remain. It's week 46 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 48 and the normal low is 32. I've calculated the 34-year averages at 46 and 32.

On the warm side, in 1987 (along with 1958 and 1966, O'Hare's warmest November 16ths) the high was 61 with a low of 50 (O'Hare's warmest low of the date and the only 50s low in its history for the date). In 2004 the high was 56 with a low of 46. The other warm highs were 65 degrees in 1975 (O'Hare's second warmest high of the date), 64 degrees in 1988 (O'Hare's third warmest high of the date) and 60 degrees in 2001. The other warm low is 44 degrees three years ago in 2009. The record high of 73 degrees was set in 1952 at Midway. The record warmest low of 53 degrees occurred back in 1931 at the University of Chicago. 16 of the past 34 highs (47%) were in the 40s. 11 highs (32%) were in the warm: 50s (8) and 60s (3). Seven highs (21%) were in the cold: 20s (1) and 30s (6). There have been no 70s highs in O'Hare's history on November 16. The two years that are tied with 1987 as O'Hare's warmest November 16ths are: 1958 (high of 63, low of 48 (O'Hare's third warmest low of the date)) and 1966 (high of 62, low of 49 (O'Hare's second warmest low of the date)). The other warm 11/16 days are in: 1971 (high of 68 (O'Hare's warmest high of the date), low of 40) and 1963 (high of 62, low of 42).

In looking back through the years to the first November at O'Hare in 1958, the following instances were notable: in 1975 the high was a warm 65 degrees. In 1971 the high was a warm 68 with a low of 40, a warm day. In 1969 the high was 51 with a cold low of 20, a 31 degree spread. In 1968 the high was 46 with a low of 42, a mere four degree spread. In 1966 the high was 62 with a low of 49, a warm day. In 1963 the high was a warm 62 with a low of 42, a warm day. In 1962 the high was 48 with a low of 43, a five degree spread. In 1959 the high was 36 with a low of 6, a 30 degree spread, cold day and year of the record low, also of 6 at Midway. This was the only 0s low ever for the date at O'Hare. In 1958 the high was 63 with a low of 48, a warm day.

More recently, there was a large spread of 32 degrees in 1988 (64/32). There were small spreads of four degrees two years ago (in 2009) (48/44), five degrees in 1993 (43/38), five degrees in 2002 (36/31), five degrees in 2003 (47/42) and six degrees in 2006 (43/37). 

On the cool side, in 1997 (O'Hare's second coolest November 16th) the high was 27 (O'Hare's only 20s high for the date) with a low of 17 (O'Hare's second coldest low of the date). In 1989 the high was 34 (O'Hare's second coolest high of the date) with a low of 18 (O'Hare's third coldest low of the date). These 10s (a.k.a. teens) lows were the only 10s lows in ORD history for the date. The other cool high of 36 degrees occurred in 2002. The record low of 6 degrees was set in 1959 at Midway. The record coolest high of 21 degrees was set back in 1933 at the University of Chicago. 25 of the last 34 lows (74%) were in the: 20s (10) and 30s (15). There were six consecutive 20s and 30s lows from 1990 through 1995. Two lows (6%) were in the cold 10s (a.k.a. teens). Seven lows (20%) were in the warm: 40s (6) and 50s (1). O'Hare's coolest November 16th was in 1959 as the high was 36 with a low of 6 (O'Hare's coldest low of the date and a low that equals the record low which was set at Midway).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:15 and sunrise is at 6:46. Sunset is at 16:30 and twilight ends at 17:01. There's a total of 9 hours, 44 minutes of daylight today and 10 hours, 46 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:17 and sunrise is at 6:47. The moon is waxing crescent. Illumination was 8% at midnight, will be 12% at noon and 16% at midnight tonight. Moonrise was at 9:41 this morning. Moonset is at 19:30 tonight. Moonrise is at 10:31 tomorrow morning. Moonlight time is 9 hours, 49 minutes which is nine minutes longer than yesterday.

Cool Fall began 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 20s, 60s and 70s occur infrequently. Thanksgiving is in six days. Pearl Harbor Day is in 21 days.