July 15: ORD

Today is July 15th. It's the 196th day of the year. 169 days remain. It's week 28 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 63. I've calculated the 31-year averages at 86 and 65.

On the hot side, in 1980 the high was 98 with the record warmest low of 82. In 1995 the high was 98 with a low of 75. In 1988 the high was the record high of 102 with a low of 70, a 32 degree spread. In 2006 the high was 97 with a low of 74. 17 of the last 31 highs were 80s. Ten highs were in the warmer: 90s (9) and 100s (1). Four highs were in the cooler 70s. Through 2010, this is the average second hottest day of the year.

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1977 the high was a hot 98 with a low of 74, a hot day. In 1967 the high was 70 with a low of 49, a cool day. That low was cooler than the record low, of which occurred this year. In 1964 the high was 88 with a low of 56, a 32 degree spread. In 1962 the high was a cool 67 with a low of 60, a seven degree spread.

More recently, there was a small spread of seven degrees in 1981 (75/68) and large spreads of 31 degrees in 2002 (91/60) and 33 degrees in 1991 (87/54).

On the cool side, there were no days of a mean of 11.5 degrees or more below normal. The cool lows were 54 in both 1987 and 1991. The record low of 52 was set in 1967. The cool highs were 70 in 1987 and 72 in 1990. The record coolest high of 65 occurred back in 1903. 17 of the last 31 lows were 60s. Six lows were in the cooler 50s. Eight lows were in the warmer: 70s (7) and 80s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 4:57 and sunrise was at 5:30. Sunset is at 20:28 and twilight ends at 21:01. There's a total of 14 hours, 58 minutes of daylight today and 16 hours, 4 minutes between twilights. Tomorrow twilight begins at 4:58 and sunrise is at 5:31. The moon is waxing crescent. Illumination was 16% at midnight, will be 21% at noon and 26% at midnight tonight. Moonrise was at 10:18 this morning. Moonset is at 22:38 and moonrise is at 11:32 tomorrow morning. Moonlight time is 12 hours, 20 minutes which is 49 minutes shorter than yesterday.

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