November 7: ORD

Today is November 7th. It's the 311th day of the year. 54 days remain. It's week 45 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 53 and the normal low is 36. I've calculated the 33-year averages at 52 and 34.

On the warm side, two years ago, in 2009, the high was 71 (our only 70s high) with a low of 46. In 2001 the high was 68 with a low of 44. The other warm high was 67 in 1982. The record high of 75 was set in 1915, a time when the official readings were taken adjacent to Lake Michigan. The record warmest low of 63 occurred in 1975 at Midway. 24 of the past 33 highs (73%) were in the: 40s (11) and 50s (13). There were eight consecutive highs in the 40s & 50s from 1993 through 2000. Seven highs (21%) were in the warm: 60s (6) and 70s (1). Two highs (6%) were in the cold: 20s (1) and 30s (1).

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 58 with a warm low of 54, a spread of four degrees and a warm day. In 1976 the high was 38 with a low of 22, a cold day. In 1975 the high was 67 with a low of 62, a spread of just five degrees, a warm day and year of the record warmest low of 63. In 1971 the high was 35 with a low of 19, a cold day. In 1967 the low was a cold 22 degrees. In 1966 the high was 71 with a low of 50, a warm day. In 1965 the low was a warm 49 degrees. In 1959 the high was 35 with a low of 20, a cold day. In 1958 the low was a cold 24 degrees.

More recently, there were large spreads of 31 degrees in 1982 (67/36) and 30 degrees in 1981 (60/30). There was a small spread of four degrees in 1998 (42/38).

On the cold side, in 1991 the high was the record coldest high of 27 with the record low of 13. A couple of years later, in 1993, the high was 41 with a low of 16. The other cold high was 38 in 1992. 19 of the last 33 lows (58%) were in the 30s. Six consecutive lows were in the 30s, from 1994 through 1999. Six lows (18%) were in the cold: 10s (2) and 20s (4). Our most recent 20s low was 26 in 2003. Eight lows (24%) were in the warm 40s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:04 and sunrise is at 6:34. Sunset is at 16:40 and twilight ends at 17:09. There's a total of 10 hours, 6 minutes of daylight today and 11 hours, 5 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:05 and sunrise is at 6:35. The moon is waxing gibbous. Illumination was 89% at midnight, will be 92% at noon and 94% at midnight tonight. Moonset is at 3:33 this morning. Moonrise is at 14:53 this afternoon. Moonset is at 4:32 tomorrow morning. Moonlight time is 12 hours, 40 minutes which is 34 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. Election Day is tomorrow. Veterans Day is in four days. Thanksgiving is in 17 days.