November 19: ORD

Today is November 19th. It's the 323rd day of the year. 42 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 46 and the normal low is 31. I've calculated the 33-year averages at 50 and 33.

On the warm side, in 1983 the high was 63 with a low of 51. In 1991 the high was 70 (our only 70s high) with a low of 44. In 1979 the high was 65 with a low of 47. Three years later, in 1982, the high was 60 with a low of 48. In 2004 the high was 55 with a low of 49, a six degree spread. The other warm highs were 63 in 1985 (our most recent 60s high), 59 in 1999 and 59 in 2007. The record high of 75 was set back in 1930 and the record warmest low of 61 occurred back in 1934. Both records occurred at a time when the official readings were taken adjacent to Lake Michigan. 24 of last 33 highs (73%) were in the: 40s (13) and 50s (11). There were 13 consecutive 40s & 50s highs from 1998 through last year, 2010. Five highs (15%) were in the warm: 60s (4) and 70s (1). All of the 60s & 70s highs occurred between 1979 and 1991. There was just one other 60s high prior to 1978: 65 in 1975. Four highs (12%) were in the cold 30s, most recently 33 in 1997.

In looking back through the years to the first November at O'Hare in 1958, the following instances were notable: in 1975 the high was a warm 65 with a low of 39, a warm day. In 1974 the low was a warm 44 degrees. In 1972 the high was 39 with a low of 33, a six degree spread. In 1971 the high was 43 with a low of 37, a six degree spread. In 1969 the high was 32 with a low of 19, a cold day. In 1968 the high was a cold 34 with a low of 27, a seven degree spread. In 1964 the high was a cold 32 with a low of 19, a cold day. In 1961 the high was a cold 33 with a low of 30, a mere three degree spread.

More recently, there was a large spread of 37 degrees in 1985 (63/26). There were small spreads of three degrees in 1992 (42/39), six degrees two years ago, in 2009 (47/41), seven degrees in 1986 (34/27) and seven degrees in 1988 (48/41).

On the cold side, in 1997 the high was 33 (our most recent 30s high) with a low of 22. In the previous year, 1996, the high was 32 with a low of 26, a six degree spread. The other cold high was 34 in 1986. The other 30s high was 37 in 1984. The record low of 10 and record coldest high of 22 were set on the same cold day way back in 1894, at a time when the official readings were taken adjacent to Lake Michigan. 26 of the last 33 lows (79%) were in the: 20s (15) and 30s (11). 12 consecutive lows were in the 20s & 30s from 1992 through 2003. Seven lows (21%) were in the warm: 40s (6) and 50s (1). The low of 51 in 1983 was the only 50s low in O'Hare's history.

We had back to back warm years. In 1982 it was 15 degrees above normal (60/48) and in 1983 it was 18 degrees above normal (63/51). We had back to back cold years. In 1996 it was 10 degrees below normal (32/26) and in 1997 it was 11.5 degrees below normal (33/22).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:18 and sunrise is at 6:48. Sunset is at 16:29 and twilight ends at 16:59. There's a total of 9 hours, 41 minutes of daylight today and 10 hours, 41 minutes between twilights. We lost a minute of daylight from yesterday. Tomorrow twilight begins at 6:19 and sunrise is at 6:50. The moon is waning crescent, having reached last quarter yesterday morning at 9:09. Illumination was 43% at midnight, will be 38% at noon and 32% at midnight tonight. Moonrise was at 0:02 this morning. Moonset is at 12:52 this afternoon. Moonrise is at 1:12 tomorrow morning. Moonlight time is 12 hours, 50 minutes which is 27 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. Thanksgiving is in five days.