August 16: ORD

Today is August 16th. It's the 228th day of the year. 137 days remain. It's week 33 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 63. I've calculated the 31-year averages at 83 and 62.

On the hot side, in 1988 the high was the co-record high of 98 with a low of 73. In 1983 the high was the co-record high of 98 with a low of 71. In 1995 the high was 94 with a low of 73. The record warmest low of 78 occurred back in 1913. There were four other 90s highs, all of them in the low 90s. There were two other 70s lows: 73 in 2003 and 70 last year. Over the last 31 years, 23 highs were: 70s (9) and 80s (14). Seven highs were in the warmer 90s and one high was in the cooler 60s.

In looking back through the years to the first August at O'Hare in 1959, the following instances were notable: In 1976 the low was a cool 49. In 1968 the high was a hot 94. In 1964 the high was 83 with a cool low of 46, a 37 degree spread. That low of 46 is cooler than the record low. In 1963 the high was 81 with a low of 51, a 30 degree spread.

More recently, there was a large spread of 30 degrees in 2004 (78/48) and a small spread of five degrees in 2001 (70/65).

On the cool side, in 1979 the high was 72 with a low of 45. That low of 45 is cooler than the record low. The record low of 48 was set in 2004. The former record low of 49 was set at Midway in 1976. The other cool low was 50 in 1992. There were three other cool highs: 66 in 1980, 70 in 1981 and 70 in 2001. The record coolest high of 65 was set way back in 1902. The official thermometer was located near Lake Michigan at the time. Over the last 31 years, 24 lows were: 50s (9) and 60s (15). Two lows were in the cooler 40s. Five lows were in the warmer 70s, including last year's low of 70.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:32 and sunrise was at 6:02. Sunset is at 19:53 and twilight ends at 20:23. There's a total of 13 hours, 51 minutes of daylight today and 14 hours, 51 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 5:33 and sunrise is at 6:03. The moon is waxing crescent and reaches first quarter today at 13:14. Illumination was 45% at midnight, will be 50% at noon and 55% at midnight tonight. Moonrise is at 14:06 this afternoon. Moonset is at 23:24 tonight. Moonrise is at 15:10 tomorrow afternoon. Moonlight time is 9 hours, 18 minutes which is 28 minutes shorter than yesterday. -Bernie-