November 19: ORD

Today is November 19th. It's the 324th day of the year. 42 days remain. It's week 47 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 46 and the normal low is 31. I've calculated the 34-year averages at 50 and 33.

On the warm side, in 1983 the high was 63 with a low of 51 (O'Hare's warmest and only 50s low of the date). In 1991 the high was 70 (O'Hare's warmest and only 70s high of the date) with a low of 44. 1983 and 1991 are O'Hare's co-warmest November 19ths. In 1979 (O'Hare's second warmest November 19th) the high was 65 (O'Hare's second warmest high of the date) with a low of 47. Three years later, in 1982, the high was 60 with a low of 48. In 2004 the high was 55 with a low of 49 (O'Hare's second warmest low of the date), a six degree spread. Last year, in 2011, the high was 58 with a low of 44. The other warm highs were 63 degrees in 1985, 59 degrees in 1999 and 59 degrees in 2007. The other warm low of 44 degrees occurred in 1974. The record high of 75 degrees was set back in 1930 and the record warmest low of 61 degrees occurred back in 1934. Both records occurred at the University of Chicago. 25 of last 34 highs (73%) were in the: 40s (13) and 50s (12). There were 14 consecutive 40s and 50s highs from 1998 through last year, 2011. Five highs (15%) were in the warm: 60s (4) and 70s (1). All of the post 1977 60s and 70s highs occurred from 1979 through 1991. Four highs (12%) were in the cold 30s. The other warm day was in 1975 as the high was 65 with a low of 39.  

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 with a low of 39, a warm day. In 1974 the low was a warm 44 degrees. In 1972 the high was 39 with a low of 33, a six degree spread. In 1971 the high was 43 with a low of 37, a six degree spread. In 1969 the high was 32 with a low of 19, a cold day. In 1968 the high was a cold 34 with a low of 27, a seven degree spread. In 1964 the high was a cold 32 with a low of 19, a cold day. In 1961 the high was a cold 33 with a low of 30, a mere three degree spread.

More recently, there was a large spread of 37 degrees in 1985 (63/26). There were additional small spreads of three degrees in 1992 (42/39), six degrees two years ago, in 2009 (47/41), seven degrees in 1986 (34/27) and seven degrees in 1988 (48/41). 

On the cool side, in 1997 (O'Hare's second coolest November 19th) the high was 33 (with 1961, O'Hare's second coolest high of the date) with a low of 22. In the previous year of 1996, the high was 32 with a low of 26, a six degree spread. The other cool highs were 33 degrees in 1961 (with 1997, O'Hare's second coolest high of the date), 34 degrees in 1968 and 34 degrees in 1986. The record low of 10 degrees and record coolest high of 22 degrees were set on the same cold day way back in 1894, at a time when the official readings were taken adjacent to Lake Michigan. 26 of the last 34 lows (76%) were in the: 20s (15) and 30s (11). O'Hare recorded 12 consecutive lows in the 20s and 30s from 1992 through 2003. Eight lows (24%) were in the warm: 40s (7) and 50s (1). O'Hare's coolest November 19ths were in: 1964 (high of 32, low of 19) and 1969 (high of 32, low of 19). Those lows of 19 degrees are also O'Hare's coldest lows of the date. To recap, O'Hare's coolest highs of 32 degrees occurred in 1964, 1969 and 1996.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:19 and sunrise is at 6:49. Sunset is at 16:28 and twilight ends at 16:59. There's a total of 9 hours, 39 minutes of daylight today and 10 hours, 40 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:20 and sunrise is at 6:51. The moon is waxing crescent, heading towards first quarter tomorrow at 8:31. Illumination was 36% at midnight, will be 41% at noon and 46% at midnight tonight. Moonrise was at 11:49 this morning. Moonset is at 22:58 tonight. Moonrise is at 12:20 tomorrow afternoon. Moonlight time is 11 hours, 9 minutes which is 32 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 three days. Pearl Harbor Day is in 18 days.