Tuesday, April 28, 2009

April 28: ORD

Today is April 28th. It's the 118th day of the year. 247 days remain. It's week 17 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 63 and the normal low is 42. I've calculated the 30-year averages at 63 and 41.


On the warm side, in 2003 the high was 77 with a low of 54. Another warm high was 79 in 2004. Another warm low was 55 in 1993. The record high of 86 was set back in 1915 and the record warmest low of 63 was set a year earlier, back in 1914.
12 of the last 30 highs were 50s. On the warmer side, 16 highs were: 60s (7) and 70s (9). On the cooler side, two highs were in the 40s.

In looking back through the years to the first April at O'Hare in 1959, the following instances were notable: in 1978 the high was 71 with a low of 37, a 34 degree spread. In 1977 the high was 47 with a low of 32, a cool day. In 1974 the high was 76 with a low of 64, a warm day. In 1971 the high was 49 with a low of 42, a seven degree spread. In 1970 the high was 79 with a low of 60, a warm day. In 1968 the high was 69 with a low of 36, a 33 degree spread. In 1967 the high was 62 with a low of 30, a 32 degree spread. In 1962 the high was 72 with a low of 41, a 31 degree spread.

More recently, we had a small spread of four degrees in 1980 (46/42). We had large spreads of 34 degrees two years ago (73/39), 33 degrees in 2000 (70/37), 31 degrees in 1981 (73/42), 31 degrees in 1992 (59/28), 31 degrees in 1997 (66/35), 31 degrees in 2004 (79/48) and 31 degrees in 2006 (68/37).

On the cool side, last year the high was 46 with a low of 35. Another cold low was the record low of 28 in 1992. Other cool highs were 46 in 1980, 50 in 1979, 50 in 1996 and 51 in 1994. The record coldest high of 39 was set way back in 1874. 26 of the last 30 lows were: 30s (13) and 40s (13). One low was in the colder 20s. Three lows were in the warmer 50s.

Today is not a major day in Chicago's snow history.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:22 and sunrise is at 5:53. Sunset is at 19:50 and twilight ends at 20:20. Tomorrow twilight begins at 5:21 and sunrise is at 5:51. There's a total of 13 hours, 57 minutes of daylight today and 14 hours, 58 minutes between twilights. The moon is waxing crescent. Illumination was 13% at midnight, will be 17% at noon and 22% at midnight tonight. Moon rise is at 8:15 and moon set is at 0:26 tomorrow. The moon will rise at 9:24 tomorrow. Moonlight time is 15 hours, 45 minutes which is 26 minutes shorter than yesterday.

National Teacher Day is in a week. Mother's Day is in 12 days. -Bernie-

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