December 6: ORD

Today is December 6th. It's the 340th day of the year. 25 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 23.

On the warm side, in 1980 the high was the record high of 65 with the record warmest low of 52. The record high of 65 was first set in 1951. In 1998 the high was 62 with a low of 37. In 2004 the high was 50 with a low of 40. Three years prior, in 2001, the high was 51 with a low of 37. Another warm high was 53 in 1988. Over the last 32 years, 16 highs (50%) were in the 30s. 11 highs (34%) were in the warmer: 40s (6), 50s (3) and 60s (2). Our most recent 40s high was 41 in 1993. Five highs (16%) were in the cold: 10s (a.k.a. teens)(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 28 with a cold low of -1, a cold day. That low of -1 was colder than the record low. In 1973 the high was 32 with a low of 25, a seven degree spread. In 1972 the high was 24 with a low of 0, a cold day. In 1971 the high was 43 with a low of 38, a five degree spread. In 1970 the high was 28 with a cold low of 11, a cold day. In 1967 the high was 46 with a warm low of 42, a four degree spread and warm day. In 1966 the high was 56 with a low of 39, a warm day. In 1964 the high was 18 with a low of -3, a cold day. That low of -3 was colder than the record low. In 1962 the high was 29 with a low of 25, a four degree spread. In 1959 the high was 31 with a low of 26, a five degree spread. In 1958 the high was 17 with a low of 5, a cold day. That high of 17 was just a degree above the record coldest high.

More recently, there was a large spread of 35 degrees in 1991 (41/6). There were small spreads of five degrees in 1994 (38/33), seven degrees in 1997 (32/25) and seven degrees in 2003 (37/30).

On the cold side, in 2005 the high was 17 with a low of 4. Two years later and three years ago (2007), the high was 24 with the record low of 0. The record low of 0 also occurred previously in 1972 and way back in 1885. In 1984 the high was 21 with a low of 8. In 2000 the high was 20 with a low of 10. Other cold lows were 6 in 1991 and 9 in 2002. The record coldest high 16 was set way back in 1893. 25 of the last 32 lows (78%) were: 10s (a.k.a. teens)(7), 20s (11) and 30s (7). Our most recent 30s low was 30 in 2003. Five lows were in the cold 0s (a.k.a. single digits). Two lows were in the warmer: 40s (1) and 50s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:36 and sunrise is at 7:08. Sunset is at 16:21 and twilight ends at 16:53. There's a total of 9 hours, 13 minutes of daylight today and 10 hours, 17 minutes between twilights. We are losing a minute of daylight per day. Tomorrow twilight begins at 6:37 and sunrise is at 7:08. The moon became new yesterday at 11:36 and is waxing crescent. Illumination was 0% at midnight, will be 1% at noon and 3% at midnight tonight. Moonrise is at 8:07 this morning. Moonset is at 17:16 this afternoon. Moonrise is at 8:55 tomorrow morning. Moonlight time is 9 hours, 9 minutes which is a minute longer than yesterday.

Pearl Harbor Day is tomorrow. Bill of Rights Day is in nine days. -Bernie-