December 12: ORD

Today is December 12th. It's the 346th day of the year. 19 days remain. It's week 50 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 35 and the normal low is 21. I've calculated the 32-year averages at 36 and 21.

On the warm side, in 1991 the high was 60 with a low of 38. The year earlier, 1990, the high was 55 with a low of 35. Most recently, in 2006, the high was 50 with a low of 38. Five years prior, in 2001, the high was 47 with a low of 38. In 1984 the high was 47 with a low of 32. Other warm highs were 48 in both 1980 and 1998. Another warm low was 35 in 1996. The record high of 61 was set way back in 1877. The record warmest low of 48 occurred in 1968. Over the last 32 years, 27 highs (84%) were in the: 20s (9), 30s (9) and 40s (9). Of those categories, the 40s occurred longest ago (44 in 2004). Three highs were in the warmer: 50s (2) and 60s (1). Two highs were in the cold 10s (aka teens). We've had examples of every high temperature category the last six years except for the extremes (10s & 60s): 44 in 2004, 28 in 2005, 50 in 2006, 36 in 2007, 21 in 2008 and 36 last year.

In looking back through the years to the first December at O'Hare in 1958, the following instances were notable: in 1976 the low was a cold 9 degrees. In 1975 the high was 38 with a warm low of 35, a mere three degree spread. Also in 1975, the temperatures yesterday and today were duplicates. In 1974 the high was 35 with a low of 31, a four degree spread. In 1970 the high was 36 with a low of 32, a four degree spread. In 1968 the high was 53 with a low of 48, a five degree spread and warm day. In 1967 the high was 42 with a warm low of 36, a six degree spread. In 1966 the high was 28 with a low of 21, a seven degree spread. In 1965 the high was 57 with a low of 44, a warm day. In 1964 the low was a warm 33 degrees. In 1963 the low was a cold 8 degrees. In 1962 the high was just 10 degrees (equaling the record coldest high) with a low of -7, a reading near the record low and a very cold day. In 1961 the low was a cold 7 degrees. In 1960 the high was a cold 23 degrees. In 1959 the high was 39 with a warm low of 34, a five degree spread. In 1958 the high was 12 with a low of 3, a very cold day.

More recently, there were no large spreads of 30 degrees or more. There were small spreads of five degrees in 1983 (36/31), five degrees in 1996 (40/35) and seven degrees in 1987 (39/32).

On the cold side, in 2000 the high was 15 with the record low of -8. In 1989 the high was 17 with a low of 5. Three years before, in 1986, the high was 21 with a low of 5. Four years before that, in 1982, the high was 23 with a low of 7. In 1995 the high was 24 with a low of 7. A decade earlier, in 1985, the high was 22 with a low of 9. Two years ago the high was 21 with a low of 11. Another cold low was 9 in 2005. The record coldest high of 10 occurred in 1962. The former record low of -7 also occurred in 1962. 19 of the last 32 lows (59%) were: 20s (9) and 30s (10). 13 lows (41%) were in the cold: negative 0s (1), 0s (aka single digits)(6) and 10s (aka teens)(6). We've had examples of every low temperature category the last five years except for the negative 0s: 9 in 2005, 38 in 2006, 23 in 2007, 11 in 2008 and 16 last year.

In 1987, Rockford had 10 inches of snow today. O'Hare only had a trace from the storm.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 6:41 and sunrise was at 7:13. Sunset is at 16:21 and twilight ends at 16:53. There's a total of 9 hours, 8 minutes of daylight today and 10 hours, 12 minutes between twilights. We are losing a minute of daylight per day. Tomorrow twilight begins at 6:42 and sunrise is at 7:14. The moon is waxing crescent, heading towards first quarter tomorrow morning at 7:59. Illumination was 38% at midnight, will be 42% at noon and 47% at midnight tonight. Moonrise is at 11:22 this morning. Moonset is at 23:30 tonight. Moonrise is at 11:44 tomorrow morning. Moonlight time is 12 hours, 8 minutes which is 38 minutes longer than yesterday.

Bill of Rights Day is in three days. Christmas Eve is in 12 days. -Bernie-