October 26: ORD

Today is October 26th. It's the 299th day of the year. 66 days remain. It's week 43 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 58 and the normal low is 40. I've calculated the 32-year averages at 57 and 41.

On the warm side, in 2000 the high was 76 with a low of 59. In 1989 the high was 75 with a low of 50. In 1996 the high was 68 with a low of 56. Last year, in 2010, the high was 70 with a low of 54. In 1998 the high was 73 with a low of 50. The other warm high was 70 in 1985. The other warm lows were 53 in 2004, 53 in 2007 and 52 in 1986. The record high of 84 was set in 1963 at Midway. The record warmest low of 63 was set back in 1939, a time when the official readings were taken adjacent to Lake Michigan. 20 of the past 32 highs (63%) were in the: 50s (12) and 60s (8). There were seven consecutive highs in the 50s & 60s from 1990 through 1996. Five highs (15%) were in the warm 70s. There were three more 70s highs and an 80s high before 1979. Seven highs (22%) were in the cold 40s.

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1974 the high was 66 with a low of 34, a 32 degree spread. In 1971 the high was 78 with a low of 57, a warm day. In 1970 the high was 72 with a low of 52, a warm day. In 1966 the high was 62 with a cold low of 25, a 37 degree spread. In 1964 the high was a warm 72 degrees. In 1963 the high was a warm 83 with a low of 45, a 38 degree spread, warm day and year of the record high of 84 at Midway. In 1962 the high was 45 with a low of 19 (colder than the record low of 22), a cold day. In 1961 the low was a cold 28 degrees. In 1959 the high was a cold 39 with a low of 34, a five degree spread and cold day.

More recently, there was a large spread of 33 degrees in 1982 (64/31). There were small spreads of three degrees in 2006 (46/43), five degrees in 2001 (41/36), six degrees two years ago, in 2009 (55/49), seven degrees in 1986 (59/52), seven degrees in 1991 (54/47) and seven degrees in 2004 (60/53).

On the cold side, in 1980 the high was 42 with a low of 26. In 1988 the high was 44 with a low of 28. Other cold highs were 41 in 2001, 45 in 2003, 46 in 1997 and 46 in 2006. The record low of 22 and record coldest high of 37 were set on the same cold day back in 1942 at Midway. The record low of 22 was originally set way back in 1887. 13 of the last 32 lows (41%) were in the 30s. Four lows (12%) were in the cold 20s. Our last low in the 20s was 28 in 1990. Two more 20s lows and a low in the 10s (a.k.a. teens) occurred before 1979. 15 lows (47%) were in the warm: 40s (7) and 50s (8).

There's an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 1988 the high was 44 with a low of 28, overall 13 degrees BELOW normal. Then in 1989 the high was 75 with a low of 50, overall 13.5 degrees ABOVE normal.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:50 and sunrise is at 7:19. Sunset is at 17:55 and twilight ends at 18:24. There's a total of 10 hours, 36 minutes of daylight today and 11 hours, 34 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:51 and sunrise is at 7:20. The moon is new today at 14:56. Illumination was 1% at midnight, will be 0% at noon and 0% at midnight tonight. Moonrise is at 7:09 this morning. Moonset is at 17:36 this afternoon. Moonrise is at 8:27 tomorrow morning. Moonlight time is 10 hours, 27 minutes which is 41 minutes shorter than yesterday.

Warm Fall began September 22 and runs for 41 days through November 1. High temperatures in this period are usually in the 50s, 60s and 70s. Highs in the 30s and 40s occur infrequently. Halloween is in five days. Election Day is in 13 days.