November 28: ORD

Today is November 28th. It's the 332nd day of the year. 33 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 41 and the normal low is 27. I've calculated the 33-year averages at 43 and 28.

On the warm side, in 2006 the high was 61 with the record warmest low of 54 (the only 50s low in Chicago's history for the date), a seven degree spread. The former record warmest low of 48 occurred in 1916. In 1998 the high was 67 with a low of 41 (our most recent 40s low). In 2005 the high was 61 with a low of 39 (our most recent 30s low). In 1997 the high was 56 with a low of 43. A decade earlier, in 1987, the high was 51 with a low of 42. The other warm high was 54 two years ago in 2009. The record high of 69 was set way back in 1905, a time when the official readings were taken adjacent to Lake Michigan. 25 of the past 33 highs (76%) were in the: 30s (13) and 40s (12). There were nine consecutive 30s & 40s highs from 1978 through 1986 and another six consecutive from 1999 through 2004. Our most recent 30s high was 37 in 2003. Seven highs were in the warmer: 50s (4) and 60s (3). The only pre-1978 high in the 60s was 63 in 1960. One high was in the cold 20s. Pre-1978, there were four highs in the 20s and a sub-20 degree high of 16 in 1976.

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 23 with a low of 7, a cold day. In 1976 the high was 16 with a low of 6, another cold day. In 1970 the high was 42 with a warm low of 40, a two degree spread. Temperatures yesterday and today in 1970 were the same! In 1968 the high was 42 with a low of 35, a seven degree spread. In 1966 the high was 35 with a low of 30, a five degree spread. In 1965 the high was a cold 29 degrees. In 1964 the high was a warm 54 with a low of 18, a 36 degree spread. In 1962 the high was a warm 56 degrees. In 1960 the high was a warm 63 with a low of 28, a 35 degree spread and warm day. Also in 1960, there was a rare 44 degree drop in temperature from the high of 63 on the 28th to a low of 19 on the 30th. In 1959 the high was a cold 24 with a low of 16, a cold day. In 1958 the high was a cold 25 with a low of 16, a cold day.

More recently, there were no other large spreads. There were small spreads of three degrees in 1980 (35/32), six degrees in 1991 (38/32), seven degrees in 1982 (41/34), seven degrees in 1994 (40/33) and seven degrees in 2001 (42/35).

On the cold side, in 1995 the high was 29 (our only 20s high) with a low of 13. In 2002 the high was 33 with a low of 15. The record low of 0 was set way back in 1887 and earlier in 1872. The record coldest high of 13 occurred way back in 1891. The records were set at a time when the official readings were taken adjacent to Lake Michigan. 24 of the last 33 lows (73%) were in the: 20s (15) and 30s (9). Five lows were in the cold 10s (a.k.a. teens). Even colder, lows were 6 in 1976 and 7 in 1977. Four lows were in the warm: 40s (3) and 50s (1). There was a warm low of 40 in 1970.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:28 and sunrise is at 6:59. Sunset is at 16:23 and twilight ends at 16:54. There's a total of 9 hours, 24 minutes of daylight today and 10 hours, 26 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:29 and sunrise is at 7:00. The moon is waxing crescent. Illumination was 12% at midnight, will be 16% at noon and 20% at midnight tonight. Moonrise is at 10:07 this morning. Moonset is at 20:11 tonight. Moonrise is at 10:44 tomorrow morning. Moonlight time is 10 hours, 4 minutes which is 24 minutes longer 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. Pearl Harbor Day is in nine days.