July 21: ORD

Today is July 21st. It's the 202nd day of the year. 163 days remain. It's week 29 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 31-year averages at 83 and 65.

On the hot side, in 2002 the high was 96 with a low of 78. 1998 was the second warmest day with a high of 94 and low of 76. 1983 was third warmest with a high of 96 and low of 72. The record high of 103 was set way back in 1901. The record warmest low of 80 occurred in 1972. 15 of the last 31 highs were 80s. Seven highs were in the warmer 90s. Nine highs were in the cooler: 60s (2) and 70s (7).

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1973 the high was 78 with a low of 71, a seven degree spread. In 1972 the high was 93 with a warm low of 79, a hot day and year of the record warmest low. In 1970 the low was a cool 51. 1970 was also the year of the record low. In 1966 the high was 81 with a cool low of 48, a 33 degree spread.

More recently, there was a large spread of 33 degrees in 1979 (86/53).

On the cool side, the coolest days were 1996 (67/55) and 1992 (67/56). These were the only 60s highs. Another cool high of 71 occurred in 1981. The coolest low of 53 occurred in 1979. The record low of 51 was set in 1970. 14 of the last 31 lows were 60s. Eight lows were in the cooler 50s. Nine lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:03 and sunrise is at 5:36. Sunset is at 20:23 and twilight ends at 20:56. There's a total of 14 hours, 47 minutes of daylight today and 15 hours, 53 minutes between twilights. Tomorrow twilight begins at 5:04 and sunrise is at 5:36. The moon is waxing gibbous. Illumination was 79% at midnight, will be 83% at noon and 86% at midnight tonight. Moonset is at 1:25 this morning. Moonrise is at 17:16. Moonset is at 2:14 tomorrow morning. Moonlight time is 8 hours, 9 minutes which is 19 minutes shorter than yesterday.

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