September 26: ORD

Today is September 26th. It's the 269th day of the year. 96 days remain. It's week 39 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 70 and the normal low is 50. I've calculated the 31-year averages at 70 and 50.

On the warm side, in 1998 the high was the record high of 90 with a low of 68. In 1986 the high was 78 with a low of 69. In 1999 the high was 86 with a low of 57. Other warm highs were 85 in 1987 and 83 in 1979. For 15 years running, there have been no highs failing to reach at least 65 degrees. The last time the high was below 65 was in 1994 when it was 58. The record warmest low of 71 was set in 1973. Over the last 31 years, 23 highs (74%) were: 60s (14) and 70s (9). Four highs were in the warmer: 80s (3) and 90s (1). Four 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 1978 the high was 76 with a low of 46, a 30 degree spread. In 1974 the high was a warm 82 with a low of 50, a 32 degree spread. In 1973 the high was 82 with a low of 71, a warm day and year of the record warmest low. In 1966 the low was a cold 36. In 1965 the high was a cool 53 with a low of 42, a cool day. In 1963 the high was a warm 83 with a low of 50, a 33 degree spread.

More recently, there were large spreads of 39 degrees in 1987 (85/46), 32 degrees in 1979 (83/51) and 31 degrees in 1995 (76/45). There was a small spread of seven degrees in 1994 (58/51).

On the cool side, in 1984 the high was 53 with the near-record low of 36 (the record low of 35 was set in 1928). The other cool highs were all 58 degrees in: 1980, 1989 and 1994. The record coolest high of 47 was set in 1942. 28 of the last 31 lows (90%) were: 40s (12) and 50s (16). One low was in the cooler 30s and two lows were in the warmer 60s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:17 and sunrise is at 6:45. Sunset is at 18:44 and twilight ends at 19:11. There's a total of 11 hours, 59 minutes of daylight today and 12 hours, 54 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 6:18 and sunrise is at 6:46. The moon is waning gibbous. Illumination was 92% at midnight, will be 90% at noon and 86% at midnight tonight. Moonset is at 10:06 this morning. Moonrise is at 19:58 tonight. Moonset is at 11:10 tomorrow morning. Moonlight time is 14 hours, 8 minutes which is 31 minutes longer than yesterday.

Columbus Day is in 15 days. -Bernie-