August 8: ORD

Today is August 8th. It's the 220th day of the year. 145 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 82 and the normal low is 64. I've calculated the 31-year averages at 84 and 65.

On the hot side, in 1983 the high was 98 with a low of 72. In 1988 the high was 99 with a low of 70. In 2001 the high was 93 with the record warmest low of 76. The other two 90s highs were 93 in 2005 and 90 in 1980. Another warm low was 75 in 1980. The record high of 100 was set in 1934. Over the last 31 years, 18 highs were 80s, five were warmer 90s and eight were cooler 70s.

In looking back through the years to the first August at O'Hare in 1959, the following instances were notable: In 1976 the high was 79 with a cool low of 49, a 30 degree spread. That low of 49 was O'Hare's lowest for the date and cooler than the official record low which was set at Midway in '76 (see below). In 1970 the high was 76 with a low of 71, a five degree spread. In 1964 the low was a cool 51, also cooler than the record low.

More recently, there were large spreads of 30 degrees in 1985 (85/55), 30 degrees in 1990 (85/55) and 30 degrees in 2005 (93/63). The small spread was seven degrees in 1987 (77/70).

On the cool side, there were no days of a mean of at least 11.5 degrees below normal. The coolest temperatures were the mid 50s lows: 53 in 1989, 54 in 1993 and three at 55. The record low of 52 was set in 1976 at Midway. The coolest highs were 72 in both 1991 and 1999. The record coolest high of 62 was set way back in 1884. The official thermometer was located near Lake Michigan at the time. Small differences in the lows over the last 31 years: the 60s have 14, the warmer 70s have ten and the cooler 50s have seven.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:22 and sunrise is at 5:53. Sunset is at 20:04 and civil twilight ends at 20:35. Nautical twilight ends at 21:13 and astronomical twilight ends at 21:54. There's a total of 14 hours, 11 minutes of daylight today and 15 hours, 13 minutes between twilights. We are losing about two minutes of daylight a day. Tomorrow twilight begins at 5:24 and sunrise is at 5:54. The moon is waning crescent and reaches new tomorrow night at 22:08. Illumination was 5% at midnight, will be 3% at noon and 1% at midnight tonight. Moonrise is at 3:57 this morning. Moonset is at 19:02 this afternoon. Moonrise is at 5:15 tomorrow morning. Moonlight time is 15 hours, 5 minutes which is 33 minutes shorter than yesterday. -Bernie-