Friday, July 24, 2009

July 24: ORD

Today is July 24th. It's the 205th day of the year. 160 days remain. It's week 30 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 84 and the normal low is 64. I've calculated the 30-year averages at 85 and 64.


On the hot side, in 2005 the high was 102 with the co-record warmest low of 78. The other co-record warmest low (also 78 degrees) occurred in 1940.
Another warm low was 75 in 1987. Another hot high was 94 in 1999. The record high of 105 was set back in 1934, the hottest temperature ever recorded in Chicago's history. An interesting sidebar was that for ten straight years from 1989 to 1998, there were no highs of 90 or above. 18 of the last 30 highs were 80s. Eight highs were in the warmer: 90s (7) and 100s (1). Four highs were in the cooler 70s.

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1964
and 1966 the highs were 92.

More recently, there w
as a large temperature spread (diurnal) of 32 degrees in 1988 as the high was 91 with a low of 59.

On the cool side, there were no days of a mean of at least 11.5 degrees below normal. In 2004 the high was just 71, the coolest high of the past 30 years. The record coolest high of 66 was set way back in 1896. Another cool high was 74 in 1992. The coolest low was the record low of 53 degrees, set in 2000. Other cool lows were 54 in 2003 and 55 in 2004. 16 of the last 30 lows were 60s. Eight lows were in the cooler 50s. Six lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:06 and sunrise is at 5:39. Sunset is at 20:21 and twilight ends at 20:53. Tomorrow twilight begins at 5:07 and sunrise is at 5:39. There's a total of 14 hours, 42 minutes of daylight today and 15 hours, 47 minutes between twilights. The moon is waxing crescent. Illumination was 7% at midnight, will be 10% at noon and 14% at midnight tonight. Moonrise is at 8:50 this morning. Moonset is at 21:47 tonight. Moonrise is at 10:05 tomorrow morning. Moonlight time is 12 hours, 57 minutes which is 52 minutes shorter than yesterday.

Parent's Day is in two days. -Bernie-

No comments: