Sunday, September 19, 2010

September 19: ORD

Today is September 19th. It's the 262nd day of the year. 103 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 73 and the normal low is 53. I've calculated the 31-year averages at 76 and 55.


On the hot side, in 1985 the high was 87 with a low of 66. In 2002 the high was 80 with a low of 72. Two years earlier, in 2000, the high was 87 with a low of 62. Five years later, in 2005, the high was 84 with a low of 65. Three years ago the high was 84 with a low of 65. Other hot highs were 87 in 1984, 85 in 1983 and 85 in 1994. The record high of 93 was set in 1955. The record warmest low of 74 occurred in 1908, a time when the official readings were taken on the lakefront.
Over the last 31 years, there have been 23 highs (74%) in the: 70s (10) and 80s (13). Eight highs have been in the cooler: 50s (2) and 60s (6).

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 90 with a low of 67, a hot day. In 1976 the high was 82 with a low of 47, a 35 degree spread. In 1974 the high was a hot 87. In 1968 the high was 62 with a low of 59, a three degree spread. In 1967 the low was a warm 65. In 1965 the high was 86 with a low of 68, a hot day. In 1963 the high was a hot 90 with a low of 63, a hot day.
In 1962 the low was a cool 39 degrees, cooler than the record low.

More recently, there were
large spreads of 34 degrees in 1984 (87/53), 33 degrees in 1999 (80/47) and 30 degrees in 1994 (85/55). There were no small spreads of up to seven degrees.

On the cool side, in 1991 the high was 56 with the record low of 40. In 2006 the high was 55 with a low of 47. The record coolest high of 52 was set back in 1938. Over the last 31 years, 15 lows were in the 50s. Eight lows were in the cooler 40s. Eight lows were in the warmer: 60s (7) and 70s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:09 and sunrise is at 6:37. Sunset is at 18:56 and twilight ends at 19:24. There's a total of 12 hours, 19 minutes of daylight today and 13 hours, 15 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 6:11 and sunrise is at 6:39. The moon is waxing gibbous. Illumination was 85% at midnight, will be 89% at noon and 91% at midnight tonight. Moonset was at 3:01 this morning. Moonrise is at 17:05 this afternoon. Moonset is at 4:02 tomorrow morning. Moonlight time is 9 hours, 56 minutes which is 35 minutes longer than yesterday.

Columbus Day is in 22 days. -Bernie-

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