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 80 and the normal low is 61. I've calculated the 31-year averages at 82 and 62.

On the hot side, there were no days of a mean of at least 11.5 degrees above normal. The warmest high was 90 three years ago. This was the first 90s high since 1976 (90). The record high of 99 was set in 1936. The three 70s lows were: 72 two years ago, 71 in 1989 and 70 in 1996. The record warmest low of 76 occurred in 1968. Over the last 31 years, 21 highs were in the 80s. One high was in the warmer 90s. Eight highs were in the cooler 70s. One high, last year's high of 68, was the only 60s high of the last 31 years. The previous 60s high occurred 42 years prior 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 1975 the low was a warm 73. In 1971 the high was a hot 93. In 1968 the high was 94 with a low of 76, a very 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 cool 49. In 1959 the high was 94 with a low of 74, a very hot day.

More recently, there was a small spread of five degrees in 1990 (72/67). There were two large spreads: 32 degrees in 1992 (83/51) and 31 degrees in 2004 (80/49).

On the cool side, there were no days of a mean of at least 11.5 degrees below normal. The coolest temperature was the record low of 49, set in 2004. The former record lows were 51 way back in 1890 and 51 in 1992. The coolest high was 68 last year. Our prior coolest high was 72 in 1990. The record coolest high of 60 occurred way back in 1890. The official thermometer was located near Lake Michigan at the time. Over the last 31 years, 19 lows were in the 60s. Nine lows were in the cooler: 40s (1) and 50s (8). Three lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:39 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, 34 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 5:40 and sunrise is at 6:09. The moon is waxing gibbous, heading towards the full Sturgeon or Grain moon in two days at 12:05. Illumination was 95% at midnight, will be 97% at noon and 98% at midnight tonight. Moonset is at 4:07 this morning. Moonrise is at 18:36 tonight. Moonset is at 5:08 tomorrow morning. Moonlight time is 9 hours, 31 minutes which is 34 minutes longer than yesterday. -Bernie-