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 83 and the normal low is 64. I've calculated the 32-year averages at 84 and 65.

On the hot side, in 1983 the high was 98 with a low of 72. Five years later, 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 record warmest low of 76 was originally set way back in 1896. The record high of 100 was set in 1934. The other 90s highs were 93 in 2005 (most recent) and 90 in 1980. Other warm lows were 75 in 1980 and 73 in 2007. Over the past 32 years, 19 highs (59%) were in the 80s, five highs (16%) were in the hot 90s and eight highs (25%) were in the cool 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 cold low of 49, a 30 degree spread. That low of 49 was O'Hare's lowest for the date and colder than the official record low which was set at Midway this same year. In 1970 the high was 76 with a low of 71, a five degree spread. In 1964 the low was a cool 51 degrees, also colder 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, in 1989 the high was 77 with a low of 53. A decade later, in 1999, the high was 72 with a low of 59. Another cool high was 72 in 1991. The record low of 52 was set in 1976 at Midway. Another cool low was 54 in 1993. The record coolest high of 62 was set way back in 1884. The official thermometer was located near Lake Michigan at the time. Over the last 32 years, 25 lows (78%) were in the: 60s (15) and 70s (10). Seven lows (22%) were in the 50s, most recently 58 in 2002.

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 twilight ends at 20:35. There's a total of 14 hours, 11 minutes of daylight today and 15 hours, 13 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 5:23 and sunrise is at 5:54. The moon is waxing gibbous, having reached first quarter two days ago at 6:08. Illumination was 70% at midnight, will be 75% at noon and 79% at midnight tonight. Moonset is at 0:42 this morning. Moonrise is at 16:21 this afternoon. Moonset is at 1:37 tomorrow morning. Moonlight time is 8 hours, 21 minutes which is 19 minutes shorter than yesterday. Moonlight time is at it's shortest today and tomorrow.

Summer began June 4 and runs for 110 days through September 21. High temperatures in this period are usually in the 70s and 80s. Highs in the 60s, 90s and 100s occur infrequently. Labor Day is in 28 days.