August 22: ORD

Today is August 22nd. It's the 234th day of the year. 131 days remain. It's week 34 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 32-year averages at 82 and 62.

On the hot side, in 1996 the high was 89 with a low of 70. In 2007 the high was 90 (our only 90s high) with a low of 69. That high of 90 was the first 90s high since 1976 when it also reached 90. The record high of 99 was set in 1936. The only other 70s lows were 72 three years ago (in 2008) and 71 in 1989. The record warmest low of 76 occurred in 1968. 22 of the past 32 highs (69%) were in the 80s. One high (3%) was in the hot 90s. Nine highs (28%) were in the cool: 60s (1) and 70s (8). The high of 68 degrees two years ago was the only 60s high of the last 32 years. The previous 60s high of 64 occurred 44 years ago in 1967. These two have been the only 60s highs in the history of O'Hare on August 22nd. Today is also the midrange date of our last 90s high of the year.

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 94 with a low of 76, a hot day. 1968 was also the year of the record warmest low. In 1967 the high was a cool 64 with a low of 59, a mere five degree spread. In 1962 the high was a hot 93 with a low of 55, a 38 degree spread. In 1961 the low was a cold 49 degrees. In 1959 the high was a hot 94 with a low of 74, a hot day.

More recently, there was a small spread of five degrees in 1990 (72/67) and a large spread of 32 degrees in 1992 (83/51).

On the cool side, two years ago, in 2009, the high was 68 (the only 60s high since 1967) with a low of 57. Five years earlier, in 2004, the high was 80 with the record low of 49. The former record lows were both 51 degrees, occurring way back in 1890 and in 1992. The record coolest high of 60 occurred way back in 1890. The official thermometer was located near Lake Michigan at the time. So as you can see, 1890 was the coldest August 22nd overall. 20 of the last 32 lows (63%) were in the 60s. Nine lows (28%) were in the cool: 40s (1) and 50s (8). Three lows (9%) were in the warm 70s. With the exception of the 40s, the last three years have seen all the categories of low temperatures: 72 in 2008, 57 in 2009 and 68 last year.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:38 and sunrise is at 6:08. Sunset is at 19:44 and twilight ends at 20:13. There's a total of 13 hours, 36 minutes of daylight today and 14 hours, 35 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 5:39 and sunrise is at 6:09. The moon is waning crescent, having passed last quarter yesterday at 16:54. Illumination was 47% at midnight, will be 42% at noon and 37% at midnight tonight. Moonset is at 14:51 this afternoon. Moonrise is tomorrow morning at 0:11. Moonset is at 15:44 tomorrow afternoon. Moonlight time is 14 hours, 51 minutes which is 21 minutes longer than yesterday.

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 14 days. 9/11 Remembrance Day and Grandparents Day are in 19 days.