November 10: ORD

Today is November 10th. It's the 314th day of the year. 51 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 51 and the normal low is 35. I've calculated the 33-year averages at 51 and 33.

On the warm side, in 1999 the high was 69 with a low of 47. Last year, in 2010, the high was 68 with a low of 43. In 2004 the high was 62 with a low of 47. The other warm highs were 64 in 1998 and 63 in 1978. The other warm low was 48 in 1992. The record high of 71 and record warmest low of 49 were set on the same day in 1949 at Midway. 23 of the past 33 highs (70%) were in the: 40s (10) and 50s (13). There were 13 consecutive highs in the 40s & 50s from 1983 through 1995. Seven highs (21%) were in the warm 60s. Three highs (9%) were in the cold 30s. There were two more 30s highs prior to 1978. O'Hare has never recorded a high of 70 or higher on November 10.

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 a cold 39 with a low of 34, a five degree spread. In 1975 the high was a warm 68 with a low of 38, a 30 degree spread. In 1974 the high was 50 with a low of 46, a four degree spread. In 1973 the high was 41 with a cold low of 18, a cold day. In 1972 the high was 45 with a low of 41, a four degree spread. In 1969 the high was 46 with a low of 41, a five degree spread. In 1960 the high was a cold 37 with a low of 24, a cold day. In 1959 the high was a warm 63 degrees.

More recently, there were no large spreads. There were small spreads of three degrees in 1992 (51/48) and four degrees in 1985 (40/36).

On the cold side, in 1996 the high was 31 with a low of 24, a seven degree spread. In 1979 the high was 34 with a low of 22. In 1986 the high was 42 with the record low of 18. The other cold low was 20 in 1991. The other cold high was 39 degrees, three years ago in 2008. The record coldest high of 28 occurred in 1926, a time when the official readings were taken adjacent to Lake Michigan. 24 of the last 33 lows (73%) were in the: 20s (11) and 30s (13). One low (3%) was in the cold 10s. There was one more low in the 10s (aka teens) prior to 1978. This low was also 18 degrees, in 1973. Eight lows (24%) were in the warm 40s. Temperatures three years ago (in 2008) and in 1991 had means of 32.5 degrees, 10.5 degrees below normal. Three years ago the high was 39 (the third 30s high since 1978) with a low of 26. In 1991 the high was 45 with a low of 20, a low just two degrees above the record.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:08 and sunrise is at 6:37. Sunset is at 16:37 and twilight ends at 17:06. There's a total of 10 hours of daylight today and 10 hours, 58 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:09 and sunrise is at 6:39. The moon is full today at 14:16 as the full Beaver (aka Frost) moon. Illumination was 100% at midnight, will be 100% at noon and 100% at midnight tonight. Moonset is at 6:30 this morning. Moonrise is at 16:23 this afternoon. Moonset is at 7:29 tomorrow morning. Moonlight time is 14 hours, 7 minutes which is 25 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. Veterans Day is tomorrow. Thanksgiving is in 14 days.