October 20: ORD

Today is October 20th. It's the 293rd day of the year. 72 days remain. It's week 42 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 60 and the normal low is 40. I've calculated the 31-year averages at 60 and 42.

On the warm side, in 1979 the high was 80 with the record warmest low of 68. In 2000 the high was 77 with a low of 55. Three years later, in 2003, the high was 85 with a low of 46, a 39 degree spread. Other warm highs were 74 in 1986 and 73 three years ago. The record high of 86 was set in 1953. Over the last 31 years, 18 highs have been 50s. 11 highs were in the warmer: 60s (5), 70s (4) and 80s (2). Two highs were in the cooler 40s.

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1978 the high was a warm 73 with a low of 35, a 38 degree spread. In 1976 the high was a cool 47 degrees. In 1975 the high was a warm 72 with a low of 40, a 32 degree spread. In 1974 the high was a cool 47 with a low of 30, a cool day. In 1972 the high was 49 with a cold low of 25, a cool day. In 1971 the high was 81 with a low of 59, a warm day. In 1970 the high was 55 with a low of 51, a four degree spread. In 1966 the high was 63 with a low of 32, a 31 degree spread. In 1965 the high was 68 with a warm low of 59, a warm day. In 1964 the high was 45 with a low of 23, a cold day. That low of 23 was cooler than the record low. In 1961 the high was a cool 48 with a low of 45, a three degree spread. In 1960 the high was a cool 45 with a low of 29, a cool day. Tom Skilling reported on his blog that back in 1952, three inches of lake-effect snow fell in Chicago but melted quickly. The high that day was just 41 with a low of 29.

More recently, there was a large spread of 35 degrees in 1986 (74/39). There were small spreads of three degrees in 2004 (53/50), four degrees in 1983 (52/48) and six degrees in 1985 (57/51).

On the cool side, in 1989 the high was 41 with a low of 34. The only other 40s high was 49 in 1995. The two 20s lows were 29 degrees, happening in 1991 and most recently in 2002. The record low of 24 was tied in 1930 (but originally set way back in 1895) and the record coolest high of 36 occurred way back in 1895. 1895 was by far the coldest of all October 20ths. 25 of the last 31 lows (81%) were: 30s (11) and 40s (14). Two lows were in the cooler 20s. Four lows were in the warmer: 50s (3) and 60s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:43 and sunrise is at 7:12. Sunset is at 18:04 and twilight ends at 18:32. There's a total of 10 hours, 52 minutes of daylight today and 11 hours, 49 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 6:45 and sunrise is at 7:13. The moon is waxing gibbous, heading towards the full Hunter's moon on Friday night at 20:36. It's also known as the Travel or Dying Grass moon. Illumination was 93% at midnight, will be 95% at noon and 97% at midnight tonight. Moonset was at 4:52 this morning. Moonrise was at 16:39 this afternoon. Moonset is at 5:53 tomorrow morning. Moonlight time is 12 hours, 13 minutes which is 37 minutes longer than yesterday.

United Nation's Day is in four days. Halloween is in 11 days. Election Day is in 13 days. Veteran's Day is in 22 days. -Bernie-