December 9: ORD

Today is December 9th. It's the 343rd day of the year. 22 days remain. It's week 49 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 36 and the normal low is 23. I've calculated the 32-year averages at 36 and 21.

On the warm side, in 1987 the high was 59 with a low of 40. In 2003 the high was 49 (our most recent 40s high) with a low of 41. A year later, 2004, the high was 50 (our most recent 50s high) with a low of 37. In 1999 the high was 53 with a low of 33. In 1990 the high was 55 with a low of 30. In 1993 the high was 51 with a low of 33. Another warm high was 48 in 1998. The record high of 62 was set way back in 1879. The record warmest low of 56 occurred back in 1946. Over the last 32 years, 14 highs (44%) were 30s. 12 highs (38%) were in the warmer: 40s (7) and 50s (5). Six highs (19%) were in the cold: 0s (1), 10s (1) and 20s (4).

In looking back through the years to the first December at O'Hare in 1958, the following instances were notable: in 1977 the high was 16 with a low of -5, a cold day. In 1974 the high was 25 with a cold low of 11, a cold day. In 1972 the high was 21 with a low of 9, a cold day. In 1971 the high was 48 with a low of 42, a six degree spread and warm day. In 1970 the high was a warm 48 degrees. In 1967 the high was 41 with a warm low of 36, a five degree spread. In 1966 the high was 38 with a low of 34, a four degree spread. In 1965 the high was a warm 50 degrees. Today in 1965 was the first of four straight highs in the 50s. In 1964 the high was 28 with a cold low of 7 degrees, a cold day. In 1962 the high was a cold 23 with a low of 13, a cold day. In 1961 the high was 32 with a low of 27, a five degree spread. In 1960 the low was a cold 11 degrees. In 1958 the high was 3 with a low of -14, a cold day. That low of -14 unofficially ties the record low. The high of 3 was near the record coldest high.

More recently, there were no large spreads of 30 degrees or more. There were small spreads of five degrees in 1994 (33/28), five degrees in 1996 (31/26), five degrees in 1997 (35/30), six degrees in 1980 (33/27) and seven degrees in 2007 (29/22).

On the cold side, in 1995 the high was 5 with a low of -4. In 1978 the high was 13 with a low of -2. In 2000 the high was 30 with a low of 2. Other cold lows were 8 in 2002, 11 in 1982 and 11 in 2005. The record low of -14 and record coldest high of 2 were set on the same day way back in 1876. 20 of the last 32 lows (63%) were: 10s (8) and 20s (12). Four lows were in the cold: negative 0s (2) and 0s (2). Eight lows were in the warmer: 30s (6) and 40s (2). Our most recent 30s low was 37 in 2004.

Three recent days (December 5, 6 and 8) have each been the third coldest of the past 33 years. In other words, they were in the top 9% of cold days for each date. Two days ago (December 7) was the fourth coldest of the date, in the top 12%.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:39 and sunrise is at 7:10. Sunset is at 16:21 and twilight ends at 16:53. There's a total of 9 hours, 11 minutes of daylight today and 10 hours, 14 minutes between twilights. We are losing a minute of daylight per day. Tomorrow twilight begins at 6:39 and sunrise is at 7:11. The moon is waxing crescent. Illumination was 13% at midnight, will be 17% at noon and 20% at midnight tonight. Moonrise is at 10:07 this morning. Moonset is at 20:28 tonight. Moonrise is at 10:35 tomorrow morning. Moonlight time is 10 hours, 21 minutes which is 32 minutes longer than yesterday.

Bill of Rights Day is in six days. Christmas Eve is in 15 days. -Bernie-