November 26: ORD

Today is November 26th. It's the 330th day of the year. 35 days remain. It's week 48 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 43 and the normal low is 28. I've calculated the 33-year averages at 46 and 29.

On the warm side, in 1984 the high was 64 with a low of 45. In 2006 the high was 62 (our most recent 60s high) with a low of 45. In 1990 the high was the record high of 67 with a low of 39. Two years before, in 1988, the high was 59 with a low of 45. A decade later, in 1998, the high was 61 with a low of 39. In 1981 the high was 62 with a low of 33. The record warmest low of 57 occurred way back in 1896, a time when the official readings were taken adjacent to Lake Michigan. 15 of the past 33 highs (46%) were in the 40s. 11 highs (33%) were in the warm: 50s (6) and 60s (5). Our most recent 50s high was 50 in 2001. The pre-1978 warm highs were 64 in 1965 and 62 in 1960. Seven highs (21%) were in the cold: 20s (2) and 30s (5). The pre-1978 cold highs were 19 in 1977 and 27 in 1958.

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 19 with a low of 2, a cold day and year of the record coldest high of 19 at Midway. That low of 2 also unofficially tied the record low set way back in 1898. In 1976 the high was a warm 58 with a low of 35, a warm day. In 1972 the high was 33 with a low of 31, a two degree spread. In 1971 the high was 39 with a low of 35, a four degree spread. In 1968 the high was a warm 55 degrees with a low of 38, a warm day. In 1966 the high was a warm 56 degrees. In 1965 the high was a warm 64 with a low of 34, a 30 degree spread and warm day. In 1961 the high was a warm 55 with a low of 39, a warm day. In 1960 the high was 62 with a low of 45, a warm day. In 1959 the high was a cold 30 with a low of 23, a seven degree spread. In 1958 the high was 27 with a low of 15, a cold day.

More recently, there were no large spreads. There were small spreads of four degrees in 2000 (41/37) and five degrees in 1987 (43/38).

On the cold side, in 1996 the high was 27 with a low of 14. Five years earlier, in 1991, the high was 37 with a low of 8. Another cold high was 29 in 2002. The record low of 2 was set way back in 1898, a time when the official readings were taken adjacent to Lake Michigan. The record coldest high of 19 was set in 1977 at Midway. 24 of the last 33 lows (73%) were in the: 20s (9) and 30s (15). Eight consecutive lows from 1997 through 2004 were in the 20s & 30s. Six lows (18%) were in the cold: 0s (1) and 10s (5). Three lows (9%) were in the warm 40s. Prior to 1978, O'Hare had lows of 2 in 1977 and 45 in 1960. In the last five years, all categories of lows were represented except the 0s (the low of 8 in 1991): 45 in 2006, 31 in 2007, 24 in 2008, 33 in 2009 and 18 in 2010.

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 1990 the high was 67 with a low of 39, overall 18 degrees ABOVE normal. Then in 1991 the high was 37 with a low of 8, overall 12.5 degrees BELOW normal.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:26 and sunrise is at 6:57. Sunset is at 16:24 and twilight ends at 16:55. There's a total of 9 hours, 27 minutes of daylight today and 10 hours, 29 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:27 and sunrise is at 6:58. The moon is waxing crescent, having passed new yesterday at 0:10. Illumination was 1% at midnight, will be 3% at noon and 6% at midnight tonight. Moonrise is at 8:29 this morning. Moonset is at 17:55 this afternoon. Moonrise is at 9:23 tomorrow morning. Moonlight time is 9 hours, 26 minutes which is a minute shorter than yesterday. Moonlight time is at it's shortest now.

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. Pearl Harbor Day is in 11 days.