November 24: ORD

Today is November 24th. It's the 328th day of the year. 37 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. 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 44 and the normal low is 29. I've calculated the 33-year averages at 43 and 27.

On the warm side, in 2001 the high was 64 with a low of 49. In 1988 the high was 59 with a low of 35. The other warm highs were 60 in 2006 (our most recent 60s high) and 58 in 1998. The other warm low was 40 degrees in 2009, two years ago. As for the extremes of the high temperatures: the 60s occurred more recently (2001 & 2006) and the 20s occurred longer ago (1982, 1985 and 1991). The record high of 69 and record warmest low of 54 were set on the same day in 1966 at Midway. 22 of the past 33 highs (67%) were in the: 30s (10) and 40s (12). Six consecutive highs from 1992 through 1997 were in the 30s & 40s. Eight highs (24%) were in the warm: 50s (6) and 60s (2). The pre-1978 60s highs were 68 in 1966 and 60 in 1974. Three highs (9%) were in the cold 20s. The one pre-1978 20s high was 25 in 1970.

In looking back through the years to the first November at O'Hare in 1958, the following instances were notable: in 1974 the high was a warm 60 degrees. In 1973 the high was 59 with a low of 45, a warm day. In 1970 the high was 25 with a low of 13, a cold day. In 1966 the high was 68 with a low of 54, a warm day. 1966 was also the year of the record high of 69 and record warmest low of 54 at Midway.

More recently, there was a large spread of 34 degrees in 1989 (44/10). There were small spreads of five degrees in 1992 (42/37) and seven degrees in 1996 (39/32).

On the cold side, in 1985 the high was 27 with a low of 11. Three years earlier, in 1982, the high was 28 with a low of 14. In 1995 the high was 34 with a low of 13. Four years earlier, in 1991, the high was 28 (our most recent 20s high) with a low of 19. The other cold lows were 10 in 1989, 16 in 1997 and 16 in 2005 (our most recent 10s low). The other cold highs were 30 in both 1983 and two decades later in 2003. The record low of -2 and record coldest high of 7 were set on the same cold day in 1950 at Midway. 31 of the last 33 lows (94%) were in the: 10s (8), 20s (11) and 30s (12). Two lows were in the warm 40s. In the last six years, all categories of lows were represented: 16 in 2005, 31 in 2006, 27 in 2007, 32 in 2008, 40 in 2009 and 25 last year.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:24 and sunrise is at 6:54. Sunset is at 16:25 and twilight ends at 16:56. There's a total of 9 hours, 31 minutes of daylight today and 10 hours, 32 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:25 and sunrise is at 6:56. The moon is waning crescent, heading towards new tomorrow at 0:10. Illumination was 2% at midnight, will be 0% at noon and 0% at midnight tonight. Moonrise is at 6:13 this morning. Moonset is at 15:56 this afternoon. Moonrise is at 7:25 tomorrow morning. Moonlight time is 9 hours, 43 minutes which is 28 minutes shorter than yesterday.

Cool Fall began November 2 and runs for 29 days through November 30. High temperatures in this period are usually in the 30s, 40s and 50s. Highs in the 10s and 20s occur infrequently. Thanksgiving is today.