September 22: ORD

Today is September 22nd. It's the 265th day of the year. 100 days remain. It's week 38 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 72 and the normal low is 51. I've calculated the 31-year averages at 71 and 51.

On the hot side, in 1986 the high was 90 with a low of 65. In 2005 the high was 87 with a low of 63. Another hot high was 84 in 1980. The other two 80s highs occurred recently: 81 two years ago and 82 in 2004. The record high of 92 was set in 1956. The record warmest low of 76 occurred in 1895, a time when the official readings were taken on the lakefront. Over the last 31 years, 24 highs (77%) were in the: 60s (11) and 70s (13). Five highs have been in the warmer: 80s (4) and 90s (1). Two highs were in the cooler 50s.

In looking back through the years to the first September at O'Hare in 1959, the following instances were notable: in 1976 the high was 71 with a cool low of 34 degrees, a 37 degree spread. In 1974 the high was 53 with a low of 32, a cool day. That low of 32 is equal to the record low. 1974 was also the year of the record coolest high. In 1970 the high was 68 with a low of 61, a seven degree spread. In 1968 the high was 83 with a warm low of 65, a warm day. In 1964 the low was a warm 64 degrees. In 1961 the high was 85 with a low of 63, a hot day. In 1959 the high was a 87 with a low of 65, a hot day.

More recently, there were large spreads of 35 degrees in 1989 (78/43), 32 degrees in 2004 (82/50) and 31 degrees in 1999 (72/41). There were no small spreads of up to seven degrees.

On the cool side, in 1995 the high was 52 with the record low of 32. In 1983 the high was 54 with a low of 37. The record coolest high of 49 was set in 1974 at Midway. Over the last 31 years, 23 lows (74%) were: 40s (12) and 50s (11). Two lows were in the cooler 30s and six lows were in the warmer 60s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:13 and sunrise is at 6:41. Sunset is at 18:51 and twilight ends at 19:19. There's a total of 12 hours, 10 minutes of daylight today and 13 hours, 6 minutes between twilights. We are losing two to four minutes of daylight a day. Tomorrow twilight begins at 6:14 and sunrise is at 6:42. The moon is waxing gibbous, heading towards the full Harvest moon tomorrow morning at 4:17. Illumination was 99% at midnight, will be 99% at noon and 100% at midnight tonight. Moonset is at 6:01 this morning. Moonrise is at 18:12 this afternoon. Moonset is at 7:01 tomorrow morning. Moonlight time is 11 hours, 49 minutes which is 39 minutes longer than yesterday. The autumnal equinox is tonight at 22:09.

Columbus Day is in 19 days. -Bernie-