August 6: ORD

Today is August 6th. It's the 218th day of the year. 147 days remain. It's week 32 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 83 and the normal low is 64. I've calculated the 31-year averages at 83 and 63.

On the hot side, there were no days of a mean of at least 11.5 degrees above normal. The warmest readings were the four 90s highs: 94 in 1984, 93 in 1988, 92 in 2001 and 90 in 1996. The warmest low was 74 three years ago. The record high of 101 was set in 1947. The record warmest low of 82 was set back in 1918. The official thermometer was located near Lake Michigan at the time. 18 of the last 31 highs were 80s. Four highs were in the warmer 90s. Nine highs were in the cooler 70s.

In looking back through the years to the first August at O'Hare in 1959, the following instances were notable: In 1968 the high was 96 with a low of 77, a hot day. In 1964 the high was 85 with a low of 54, a 31 degree spread.

More recently, there were large spreads of 35 degrees in 1988 (93/58) and 30 degrees in 1987 (87/57).

On the cool side, in 1994 the high was 72 with the record low of 48. Other cool highs were 70 in 1990, 72 in 1986 and 72 in 1989. The record coolest high of 65 was set way back in 1893. The official thermometer was located near Lake Michigan at the time. 24 of the last 31 lows were: 50s (9) and 60s (15). One low was in the cooler 40s. Six lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:20 and sunrise was at 5:51. Sunset is at 20:06 and civil twilight ends at 20:37. Nautical twilight ends at 21:16 and astronomical twilight ends at 21:58. There's a total of 14 hours, 15 minutes of daylight today and 15 hours, 17 minutes between twilights. We are losing about two minutes of daylight a day. Tomorrow twilight begins at 5:21 and sunrise is at 5:52. The moon is waning crescent. Illumination was 20% at midnight, will be 16% at noon and 12% at midnight tonight. Moonrise was at 1:36 this morning. Moonset was at 17:30 this afternoon. Moonrise is at 2:42 tomorrow morning. Moonlight time is 15 hours, 54 minutes which is 2 minutes longer than yesterday. Moonlight time peaked today. -Bernie-