October 5: ORD

Today is October 5th. It's the 278th day of the year. 87 days remain. It's week 40 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.

According to the National Climatic Data Center (NCDC), the normal high is 67 and the normal low is 46. I've calculated the 32-year averages at 66 and 44.

On the warm side, in 2005 the high was 84 with the record warmest low of 69. The former record warmest low of 68 occurred in 1922. In 2007 the high was 84 with a low of 62. In 1982 the high was 86 with a low of 54, a 32 degree spread. In 1997 the high was the record high of 88 with a low of 52, a 36 degree spread. In 1990 the high was 85 with a low of 51, a 34 degree spread. The other warm low was 58 in 1998. 17 of the past 32 highs (53%) were in the 60s. Seven highs (22%) were in the warm: 70s (2) and 80s (5). The 70s highs occurred 13 years ago (71 in 1998) and 28 years ago (70 in 1983). Eight highs (25%) were in the cool 50s, most recently 57 in 2003.

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1975 the high was 75 with a low of 42, a 33 degree spread. In 1972 the high was 64 with a warm low of 59, a five degree spread. In 1971 the high was a warm 79 degrees. In 1970 the high was also a warm 79 degrees. In 1969 the low was a warm 58 degrees. In 1968 the low was a cold 32 degrees. In 1966 the high was 61 with a cold low of 31, a 30 degree spread. In 1965 the high was 60 with a cold low of 30, a 30 degree spread. In 1963 the high was a hot 86 degrees with a low of 45, a 41 degree spread. A spread of 40 degrees or more is rare. In 1960 the high was a warm 79 degrees. In 1959 the low was a warm 58 degrees.

More recently, there were large spreads of 30 degrees in 1996 (69/39) and 30 degrees in 1993 (64/34). There was a small spread of four degrees in 1995 (60/56).

On the cool side, in 1980 the high was 54 with the record low of 28. In 1988 the high was 54 with a low of 32. The other cold lows were 31 in 2004 and 34 in 1993. The other cool high was 51 in 2001. The record coolest high of 46 occurred back in 1932. 23 of the last 32 lows (72%) were in the: 30s (10) and 40s (13). One low was in the cold 20s. Eight lows were in the warm: 50s (6) and 60s (2). The last 50s low occurred 13 years ago in 1998 at 58 degrees.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:26 and sunrise is at 6:54. Sunset is at 18:28 and twilight ends at 18:56. There's a total of 11 hours, 34 minutes of daylight today and 12 hours, 30 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:28 and sunrise is at 6:56. The moon is waxing gibbous, having reached first quarter two nights ago at 22:15. Illumination was 62% at midnight, will be 67% at noon and 71% at midnight tonight. Moonset was at 0:34 this morning. Moonrise is at 15:14 this afternoon. Moonset is at 1:38 tomorrow morning. Moonlight time is 9 hours, 20 minutes which is two 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. Columbus Day is in five days.