December 4: ORD

Today is December 4th. It's the 338th day of the year. 27 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 38 and the normal low is 24. I've calculated the 32-year averages at 38 and 25.

On the warm side, in 1998 the high was the record high of 66 with the record warmest low of 56. Three years later, in 2001, the high was 62 (our most recent 60s high) with a low of 54. Two years prior, in 1999, the high was 54 (our most recent 50s high) with a low of 44. Five years before, in 1994, the high was 56 with a low of 39. In 1982 the high was 47 with a low of 38. Over the last 32 years, 27 highs (84%) were in the: 20s (7), 30s (12) and 40s (8). Four highs were in the warmer: 50s (2) and 60s (2). One high was in the cold 10s (a.k.a. teens).

In looking back through the years to the first December at O'Hare in 1958, the following instances were notable: in 1977 the low was a cold 12 degrees. In 1976 the high was 21 with a low of 6, a cold day. In 1975 the high was a warm 53 degrees. In 1973 the high was 58 with a low of 42, a warm day. In 1971 the high was 41 with a low of 34, a seven degree spread. In 1968 the high was 41 with a low of 35, a six degree spread. In 1965 the high was 38 with a low of 32, a six degree spread. In 1963 the low was a cold 10 degrees. In 1962 the high was a warm 52 with a low of 35, a warm day. In 1961 the high was a warm 62 with a low of 31, a 31 degree spread and warm day. In 1960 the high was 58 with a low of 45, a warm day. In 1959 the high was 49 with a warm low of 37, a warm day.

More recently, there were no large spreads. There were small spreads of five degrees in 1983 (37/32), five degrees in 2003 (39/34), five degrees last year (28/23) and six degrees in 1997 (35/29).

On the cold side, in 1991 the high was the record coldest high of 13 (the former record coldest high of 18 occurred way back in 1895) with a low of 3. Twenty-five years later, in 2006, the high was 26 with a low of 6. Two years ago the high was 22 with a low of 12. In 1984 the high was 24 with a low of 12. In 2002 the high was 28 with a low of 10. Other cold lows were 8 in 1978 and 12 in 2005. The record low of 0 was set way back in 1893. 21 of the last 32 lows (66%) were: 10s (8) and 20s (13). Three lows were in the cold 0s. Eight lows were in the warmer: 30s (5), 40s (1) and 50s (2). Our most recent 30s low was 34 in 2003.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:34 and sunrise is at 7:06. Sunset is at 16:21 and twilight ends at 16:53. There's a total of 9 hours, 15 minutes of daylight today and 10 hours, 19 minutes between twilights. We are losing a minute or two of daylight per day. Tomorrow twilight begins at 6:35 and sunrise is at 7:07. The moon is waning crescent and will be new tomorrow at 11:36. Illumination was 3% at midnight, will be 1% at noon and 0% at midnight tonight. Moonrise is at 6:03 this morning. Moonset is at 15:24 this afternoon. Moonrise is at 7:09 tomorrow morning. Moonlight time is 9 hours, 21 minutes which is 25 minutes shorter than yesterday.

Pearl Harbor Day is in three days. Bill of Rights Day is in 11 days. -Bernie-