September 8: ORD

Today is September 8th. It's the 251st day of the year. 114 days remain. It's week 36 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 76 and the normal low is 56. I've calculated the 31-year averages at 79 and 59.

On the hot side, in 1985 the high was 94 with a low of 67. Six years later, in 1991, the high was 88 with a low of 67. Other warm highs were 92 in 2002 and 90 in 1983. The record high of 96 was set in 1960 at Midway. The record warmest low of 76 occurred way back in 1922, a time when the official thermometer was located adjacent to Lake Michigan. Over the last 31 years, 25 highs (81%) were: 70s (12) and 80s (13). Three highs were in the warmer 90s. Three highs were in the cooler 60s.

In looking back through the years to the first September at O'Hare in 1959, the following instances were notable: in 1978 the high was 95 with a low of 68, a hot day. In 1976 the high was 90 with a low of 57, a 33 degree spread. In 1971 the high was 94 with a low of 69, a hot day. In 1967 the high was 83 with a low of 50, a 33 degree spread. In 1966 the high was 81 with a cool low of 44, a 37 degree spread. In 1965 the high was 67 with a low of 61, a six degree spread. In 1964 the high was 92 with a low of 70, a hot day. In 1960 the high was 93 with a low of 69, a hot day and year of the record high. In 1959 the high was 97 (warmer than the record high) with a low of 71, a hot day.

More recently, there were large spreads of 38 degrees in 1983 (90/52), 32 degrees in 2002 (92/60) and 30 degrees in 1986 (73/43). There were no small spreads of up to seven degrees.

On the cool side, there were no days of a mean of at least 11.5 degrees below normal. The coolest lows were those in the 40s: the record low of 43 in 1986 and a low of 47 four years earlier in 1982. The coolest highs were those in the 60s: 65 in 1995, 66 in 1979 and 67 two years ago. The record coolest high of 54 occurred way back in 1883, a time when the official thermometer was located adjacent to Lake Michigan. Over the last 31 years, 29 lows (94%) were: 50s (12) and 60s (17). Two lows were in the cooler 40s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:58 and sunrise is at 6:26. Sunset is at 19:15 and twilight ends at 19:44. There's a total of 12 hours, 49 minutes of daylight today and 13 hours, 46 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 5:59 and sunrise is at 6:27. The moon is new this morning at 5:30. Illumination was 0% at midnight, will be 0% at noon and 1% at midnight tonight. Moonrise is at 6:44 this morning. Moonset is at 19:04 tonight and moonrise is at 8:02 tomorrow morning. Moonlight time is 12 hours, 20 minutes which is 50 minutes shorter than yesterday.

Patriot Day is in three days and Grandparent's Day is in four days. -Bernie-