August 2: ORD

Today is August 2nd. It's the 214th day of the year. 151 days remain. It's week 31 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 85 and 64.

On the hot side, in 1988 the high was the former record high of 100 with the record warmest low of 79. In 2006 the high was 97 with a low of 77. In 1991 the high was the record high of 101. Another hot high was 96 in 1987. 16 of the last 31 highs were 80s. Eight highs were in the warmer: 90s (6) and 100s (2). Seven highs were in the cooler 70s, including last year's high of 78.

In looking back through the years to the first August at O'Hare in 1959, the following instances were notable: In 1975 the high was 78 with a low of 73, a five degree spread. In 1966 the high was 71 with a low of 52, a cool day. In 1965 the high was 73 with a cool low of 49, a cool day. That low of 49 is cooler than the record low. In 1964 the high was 96 with a low of 76, a hot day. In 1962 the high was 83 with a low of 53, a 30 degree spread.

More recently, there was a large spread of 34 degrees in 1991 (101/67).

On the cool side, there were no days of a mean of at least 11.5 degrees below normal. 1985 stands out as the coolest and that's because it had the record low of 51. The high was 77 that day. 1994 and 1996 also had highs of 77, the coolest highs of the past 31 years. The record coolest high of 63 occurred back in 1927. The official thermometer was located near Lake Michigan at the time. 16 of the last 31 lows were 60s. Nine lows were in the cooler 50s, including last year's 58. Six were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:16 and sunrise is at 5:47. Sunset is at 20:11 and civil twilight ends at 20:43. Nautical twilight ends at 21:22 and astronomical twilight ends at 22:05. There's a total of 14 hours, 24 minutes of daylight today and 15 hours, 27 minutes between twilights. We are losing about two minutes of daylight a day. Tomorrow twilight begins at 5:17 and sunrise is at 5:48. The moon is waning gibbous and reaches last quarter tonight at 23:59, a minute to midnight. Illumination was 60% at midnight, will be 55% at noon and 50% at midnight tonight. Moonset is at 13:20 this afternoon. Moonrise is at 23:19 tonight. Moonset is at 14:25 tomorrow afternoon. Moonlight time is 14 hours, 1 minute which is 33 minutes longer than yesterday. -Bernie-