November 15: ORD

Today is November 15th. It's the 320th day of the year. 46 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 49 and the normal low is 33. I've calculated the 34-year averages at 48 and 34.

On the warm side, in 1990 the high was 70 (O'Hare's warmest high of the date and its only 70s high of the date) with a low of 52. In 2001 the high was 68 (with 1971, O'Hare's second warmest high of the date) with a low of 54 (O'Hare's second warmest low of the date). 1990 and 2001 are O'Hare's co-warmest November 15th days. In 1988 the high was 65 with a low of 47. The other warm highs were 64 degrees last year (in 2011), 63 degrees in 1987 and 62 degrees in 1981. The other warm low was 45 degrees in 1962. The record high of 71 degrees was set in 1971 at Midway. The record high of 71 was originally set in 1953 and two years later in 1955, both at Midway. The record warmest low of 60 degrees occurred in 1960 at Midway. 16 of the past 34 highs (47%) were in the 40s. 13 highs (38%) were in the warm: 50s (7), 60s (5) and 70s (1). Five highs (15%) were in the cold 30s, most recently 39 degrees in 2000. O'Hare's second warmest November 15th was in 1960 as the high was 65 with a low of 55 (O'Hare's warmest low of the date). The other warm 11/15 days were in: 1964 (high of 62, low of 53), 1971 (high of 68 (with 2001, O'Hare's second warmest high of the date), low of 41) and 1958 (high of 61, low of 46).

In looking back through the years to the first November at O'Hare in 1958, the following instances were notable: in 1976 the low was a cold 17 degrees. In 1972 the high was 38 with a low of 32, a mere six degree spread. In 1971 the high was a warm 68 with a low of 41, a warm day and year of the record high of 71 at Midway. In 1969 the high was 32 with a low of 20, a cold day. In 1968 the high was 46 with a low of 43, a mere three degree spread. In 1967 the high was 38 with a cold low of 20, a cold day. In 1964 the high was 62 with a low of 53, a warm day. In 1962 the low was a warm 45 degrees. In 1960 the high was 65 with a low of 55, a warm day and year of the record warmest low of 60 at Midway. In 1959 the high was 38 with a cold low of 13 degrees, a cold day. In 1958 the high was 61 with a low of 46, a warm day.

More recently, there was a large spread of 30 degrees last year, in 2011 (64/34). There were small spreads of four degrees in 2002 (40/36), four degrees in 2003 (42/38), four degrees in 2006 (47/43), six degrees in 1993 (44/38), seven degrees in 1979 (47/40), seven degrees in 1985 (42/35), seven degrees in 1998 (46/39) and seven degrees in 2008 (42/35). 

On the cool side, in 1982 (O'Hare's coolest November 15th) the high was 34 with a low of 13 (with 1959, O'Hare's coldest low of the date). In 1995 the high was 34 with a low of 20. Three years earlier, in 1992, the high was 36 with a low of 21. Five years later, in 1997, the high was 34 with a low of 24. The highs of 34 degrees just mentioned are O'Hare's second coolest highs of the date. O'Hare's second coldest low of 17 degrees occurred in 1976. The record low of 10 degrees and record coolest high of 18 degrees were set on the same cold day back in 1933 at the University of Chicago. 20 of the last 34 lows (59%) were in the 30s. Eight lows (23%) were in the cold: 10s (1) and 20s (7). Six lows (18%) were in the warm: 40s (4) and 50s (2). O'Hare's second coolest November 15th was in 1959 as the high was 38 with a low of 13 (with 1982, O'Hare's coldest low of the date). The other cool days were in: 1969 (high of 32 (O'Hare's coolest high of the date), low of 20) and 1967 (high of 38, low of 20). 


The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:14 and sunrise is at 6:44. Sunset is at 16:31 and twilight ends at 17:01. There's a total of 9 hours, 47 minutes of daylight today and 10 hours, 47 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:15 and sunrise is at 6:46. The moon is waxing crescent, having reached new two days ago at 16:08. Illumination was 3% at midnight, will be 5% at noon and 8% at midnight tonight. Moonrise was at 8:42 this morning. Moonset is at 18:22 tonight. Moonrise is at 9:41 tomorrow morning. Moonlight time is 9 hours, 40 minutes which is six minutes shorter than yesterday. Moonlight time is at its least today for the next several days.

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 seven days. Pearl Harbor Day is in 22 days.