October 3: ORD

Today is October 3rd. It's the 276th day of the year. 89 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 68 and the normal low is 47. I've calculated the 32-year averages at 67 and 47.

On the warm side, in 2005 the high was 85 with the record warmest low of 70. The former record warmest low of 69 occurred back in 1922. In 1997 the high was 87 (our warmest high) with a low of 60. In 1983 the high was 80 with a low of 61. In 2006 the high was 82 (our most recent 80s high) with a low of 55. The other warm highs were 82 in 1992 and 81 in 1990. The other warm low was 61 in 1986. The record high of 91 was set in 1954. 24 of the past 32 highs (75%) were in the: 50s (7), 60s (7) and 70s (10). Six highs were in the 80s. Two highs (the record coolest of 47 in 1999 and 49 in 1980) were in the 40s.

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1976 the high was a warm 83 with a low of 51, a 32 degree spread. In 1975 the high was 71 with a low of 38, a 33 degree spread. In 1974 the high was 60 with a cold low of 28, a 32 degree spread and cool day. That low of 28 was colder than the record low. In 1967 the high was 81 with a low of 61, a warm day. In 1964 the high was 76 with a low of 44, a 32 degree spread. In 1961 the high was 60 with a cold low of 30, a 30 degree spread and cool day.

More recently, there were large spreads of 38 degrees in 1993 (71/33), 34 degrees in 2004 (70/36), 32 degrees in 1984 (75/43), 31 degrees in 1992 (82/51), 31 degrees in 1985 (68/37), 30 degrees in 1990 (81/51) and 30 degrees in 1982 (75/45). There were small spreads of five degrees in 2002 (63/58) and seven degrees in 1998 (58/51).

On the cool side, in 1987 the high was 54 with a low of 31. In 1980 the high was 49 with a low of 37. In 1999 the high was the record coolest high of 47 with a low of 41, a six degree spread. In 1989 the high was 53 with a low of 35. In 1981 the high was 61 with the record low of 29, a 32 degree spread. The other cold low was 33 in 1993. The other cool highs were 53 in 2003, 55 in 1996 and 56 last year, in 2010. 27 of the last 32 lows (84%) were in the: 30s (7), 40s (10) and 50s (10). One low was in the cold 20s (the record low of 29 in 1981). Four lows were in the warm: 60s (3) and 70s (1), including the record warmest low of 70 in 2005.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:24 and sunrise is at 6:52. Sunset is at 18:32 and twilight ends at 19:00. There's a total of 11 hours, 40 minutes of daylight today and 12 hours, 36 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:25 and sunrise is at 6:53. The moon reaches first quarter today at 22:15. Illumination was 41% at midnight, will be 46% at noon and 51% at midnight tonight. Moonrise is at 13:56 this afternoon. Moonset is at 23:30 tonight. Moonrise is at 14:38 tomorrow afternoon. Moonlight time is 9 hours, 34 minutes which is 12 minutes longer 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 seven days.