July 23: ORD

Today is July 23rd. It's the 204th day of the year. 161 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 31-year averages at 82 and 63.

On the hot side, there were no days in which the mean was at least 11.5 degrees above normal. The hot highs were 94 in 1979 and repeated two decades later in 1999. The record high of 99 was set way back in 1914. The warm lows were 74 in 1984 and 73 in both 1983 and 2001. The record warmest low of 78 occurred in 1965. 17 of the last 31 highs were 80s. Four highs were in the warmer 90s. Ten highs were in the cooler: 60s (1) and 70s (9).

In looking back through the years to the first July at O'Hare in 1959, the following instance was notable: In 1972 the low was a warm 77 degrees.

More recently, there were no other large or small daily temperature spreads.

On the cool side, in 1992 the high was the record coolest high of 64 with a low of 60, a small four degree spread. In 2000 the high was 73 with a low of 52. The high was just 73 in 2004 as well. The record low of 51 was set in 1947. 19 of the last 31 lows were 60s. Seven lows were in the cooler 50s. Five lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:05 and sunrise was at 5:37. Sunset is at 20:22 and twilight ends at 20:54. There's a total of 14 hours, 45 minutes of daylight today and 15 hours, 49 minutes between twilights. Tomorrow twilight begins at 5:06 and sunrise is at 5:38. The moon is waxing gibbous. Illumination was 93% at midnight, will be 95% at noon and 97% at midnight tonight. Moonset was at 3:10 this morning. Moonrise is at 18:55. Moonset is at 4:10 tomorrow morning. Moonlight time is 8 hours, 15 minutes which is 11 minutes longer than yesterday.

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