August 26: ORD

Today is August 26th. It's the 238th day of the year. 127 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 79 and the normal low is 60. I've calculated the 31-year averages at 82 and 64.

On the hot side, in 1993 the high was 94 with a low of 74. A decade later, in 2003, the high was 92 with a low of 71. The other 90s highs were 93 in 1991, 92 in 1980 and 91 in 1995. The only other 70s low was 70 in 1990. The record high of 97 and record warmest low of 77 were set on the same day in 1973. Over the last 31 years, 16 highs were 80s. Five highs were in the warmer 90s. Ten highs were in the cooler: 60s (1) and 70s (9).

In looking back through the years to the first August at O'Hare in 1959, the following instances were notable: In 1973 the high was 93 with a low of 75, a hot day. This was the year that the records were set at Midway Airport. In 1968 the high was a cool 65. In 1964 the high was 74 with a cool low of 41, a 33 degree spread and cool day. That low of 41 was cooler than the record low. In 1959 the high was 92 with a low of 74, a hot day.

More recently, there were no small spreads of up to seven degrees or large spreads of at least 30 degrees.

On the cool side, there were no days of a mean of at least 11.5 degrees below normal. The coolest temperature was 54 degrees in 1988. The record low of 47 was set way back in 1887. The coolest high was 65 degrees in 1987. The record coolest high of 61 occurred way back in 1885. Over the last 31 years, 21 lows were in the 60s. Seven lows were in the cooler 50s. Three lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:43 and sunrise was at 6:12. Sunset is at 19:37 and twilight ends at 20:06. There's a total of 13 hours, 25 minutes of daylight today and 14 hours, 23 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 5:44 and sunrise is at 6:13. The moon reached full two days ago as the full Sturgeon or Grain moon at 12:05, just after noon and is waning gibbous today. Illumination was 98% at midnight, will be 96% at noon and 94% at midnight tonight. Moonset was at 8:08 this morning and moonrise is at 20:07 tonight. Moonset is at 9:08 tomorrow morning. Moonlight time is 12 hours, 1 minute which is 38 minutes longer than yesterday. -Bernie-