August 29: ORD

Today is August 29th. It's the 241st day of the year. 124 days remain. It's week 35 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 81 and 61.

On the hot side, in 1984 the high was 94 with a low of 71. In 1991 the high was 92 with a low of 73. In 1995 the high was 88 with a low of 73. The other 90s highs were 94 in 1983 and 92 in 1980. The other 70s low was 70 in 2000. The record high of 98 was set in 1953. The record warmest low of 74 was set in 1973. Over the last 31 years, 25 highs were: 70s (10) and 80s (15). Four highs were in the warmer 90s and two highs were in the cooler 60s (69 last year and the same five years earlier in 2004).

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 72. In 1973 the high was 92 with a low of 73, a hot day. 1973 was the year of the record warmest low. In 1971 the high was 84 with a low of 53, a 31 degree spread. In 1965 the high was 66 with a low of 41, a cool day. In 1964 the high was 83 with a low of 52, a 31 degree spread. In 1962 the high was a hot 92 with a low of 59, a 33 degree spread. In 1959 the temperatures for today (the 29th) and tomorrow (the 30th) were the same: a high of 86 with a low of 69.

More recently, there was a large spread of 30 degrees in 1983 (94/64).

On the cool side, in 1986 the high was 71 with a low of 44. In 1982 the high was 72 with the co-record low of 43. The record low was also 43 in 1965. Another cool low was 48 in 1988. The record coolest high of 62 occurred way back in 1893. Over the last 31 years, 24 lows were in the 50s (9) and 60s (15). Three lows were in the cooler 40s. Four lows were in the warmer 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:46 and sunrise is at 6:15. Sunset is at 19:32 and twilight ends at 20:01. There's a total of 13 hours, 17 minutes of daylight today and 14 hours, 15 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 5:48 and sunrise is at 6:17. The moon is waning gibbous. Illumination was 82% at midnight, will be 78% at noon and 74% at midnight tonight. Moonset is at 11:11 this morning and moonrise is at 21:22 tonight. Moonset is at 12:14 tomorrow afternoon. Moonlight time is 13 hours, 49 minutes which is 34 minutes longer than yesterday.

Labor Day is in eight days. -Bernie-