October 12: ORD

Today is October 12th. It's the 285th day of the year. 80 days remain. It's week 41 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 64 and the normal low is 44. I've calculated the 32-year averages at 65 and 44.

On the warm side, three years ago, in 2008, the high was the record-tying high of 84 with a low of 57. The other record highs of 84 occurred in 1956 and 1960. In 1997 the high was 82 with a low of 58. Two years earlier, in 1995, the high was 83 with a low of 55. The other warm highs of 76 occurred in 1985 and last year, in 2010. The record warmest low of 67 occurred back in 1928, a time when the official readings were taken adjacent to Lake Michigan. 20 of the past 32 highs (63%) were in the: 60s (11) and 70s (9). Three highs (9%) were in the warm 80s. 3 of O'Hare's 4 highs (75%) in the 80s on October 12th occurred in the past 32 years. Nine highs (28%) were in the cool or cold: 30s (1), 40s (2) and 50s (6). Five of the 70s highs occurred within a seven year span from 1996 to 2002. In 2006, the lone 30s high of 39 occurred. 2006 was also the year of the earliest measurable snowfall. An inch fell here in Crystal Lake and in neighboring Algonquin. An inch and a half fell at Arlington Heights. Both O'Hare and Midway airports received three tenths of an inch. The suburb of DeKalb had half an inch. October 12, 2006 beat October 18 in 1972 and 1989, the previous earliest dates for snow.

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 79 with a low of 57, a warm day. In 1975 the high was a warm 76 with a low of 41, a 35 degree spread. In 1973 the high was 74 with a warm low of 61, a warm day. In 1971 the high was 70 with a low of 39, a 31 degree spread. In 1969 the high was 61 with a low of 54, a seven degree spread. In 1968 the high was 75 with a low of 44, a 31 degree spread. In 1967 the high was 63 with a cold low of 28, a 35 degree spread. In 1966 the high was 65 with a cold low of 31, a 34 degree spread. In 1962 the high was a warm 76 degrees. In 1961 the high was a warm 78 with a low of 45, a 33 degree spread. In 1960 the high was a warm 82 with a low of 53, a warm day. 1960 was also the year of the co-record high of 84 at Midway. In 1959 the low was a cold 32 degrees.

More recently, there were large spreads of 32 degrees in 1990 (64/32), 32 degrees in 1994 (67/35), 31 degrees in 1987 (59/28) and 30 degrees in 2000 (73/43). There was a small spread of seven degrees two years ago, in 2009 (48/41).

On the cool side, in 2006 the high was 39 (our only 30s high) with a low of 30. In 1988 the high was 48 with the co-record low of 28. In 1980 the high was 53 with a low of 31. The other cool highs were 48 in 2009 and 51 in 1979. The other cold lows were the co-record low of 28 in 1987 and 32 in 1990. The record coolest high of 38 occurred back in 1917, a time when the official readings were taken adjacent to Lake Michigan. 13 of the last 32 lows (41%) were in the 40s. Ten lows (31%) were in the cold: 20s (2) and 30s (8). Note that the 20s lows were 28 degrees and that they occurred in the back-to-back years of 1987 and 1988. Nine lows (28%) were in the warm 50s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:34 and sunrise is at 7:02. Sunset is at 18:17 and twilight ends at 18:45. There's a total of 11 hours, 15 minutes of daylight today and 12 hours, 11 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:35 and sunrise is at 7:03. The moon is waning gibbous, having reached the full Hunter's moon last night at 21:06. This moon is also referred to as the Travel or Dying Grass moon. Illumination was 100% at midnight, will be 99% at noon and 99% at midnight tonight. Moonset is at 7:39 this morning. Moonrise is at 18:17 tonight. Moonset is at 8:38 tomorrow morning. Moonlight time is 13 hours, 22 minutes which is 31 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. United Nations Day is in 12 days.