December 15: ORD

Today is December 15th. It's the 350th day of the year. 16 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. Observations have been official at O'Hare since Thursday, January 17, 1980.

According to the National Climatic Data Center (NCDC), the normal high is 34 and the normal low is 20. The 30-year averages are 38 and 23.

On the warm side, in 1998 the high was 51 with a low of 37. In 1992 the high was 56 with a low of 31. In 1993 the high was 46 with a low of 38. In 1984 the high was 50 with a low of 33. In 1990 the high was 45 with a low of 34. Other warm highs were 47 in 1986 and 46 in the back-to-back years of 1996 and 1997. Other warm lows were 33 in both 1982 and 1999. The record high of 64 was set in 1971 and the record warmest low of 44 was set in 1928. 22 of the last 30 highs were 30s (12) and 40s (10). Three highs were warmer 50s. Four highs were 20s and one high was in the 10s.

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 39 with a low of 32, a seven degree spread. In 1974 the high was 43 with a low of 36, a seven degree spread. In 1973 the high was 28 with a low of 26, a two degree spread. In 1971 the high was 62 with a low of 39, a bonus 60 degree day. This was also the year of the record high of 64 degrees at Midway. In 1964 the high was 30 with a low of 1, a cold day. In 1963 the high was 11 with a low of -6, a cold day. In 1958 the high was 14 with a low of -9, yet another cold day.

More recently, we had small spreads of five degrees in 1982 (38/33) and 1999 (38/33). There was a spread of six degrees last year (31/25).

On the cold side, in 1989 the high was 16 with a low of -8. In 2000 the high was 31 with a low of 3. In 1988 the high was 27 with a low of 7. In 1981 the high was 22 with a low of 12. Another cold low was 7 in 1991. The record low of -12 and record coldest high of -2 occurred in 1901. 21 of the last 30 lows were 20s (11) and 30s (10). Five lows were 10s, three were 0s and one was a negative 0.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:44 and sunrise is at 7:15. Chicago's twilight begins at 6:40 and sunrise is at 7:12. Crystal Lake's sunset is at 16:22 and twilight ends at 16:54. Chicago's sunset is at 16:21 and twilight ends at 16:52. There's a total of 9 hours, 7 minutes of daylight today and 10 hours, 10 minutes between twilights. Tomorrow twilight begins at 6:44 and sunrise is at 7:16. The full Cold moon was Friday at 10:37. The moon is waning gibbous. Illumination was 90% at midnight, will be 87% at noon and 82% at midnight tonight. Moonset is at 10:01 and moonrise is at 20:07. Moonlight time is 13 hours, 54 minutes today.

Today is a major snow day in O'Hare's history. In 1987, 8.0 inches fell. This was day two of a two day, 9.1 inch storm. In 1973, 3.2 inches fell. This was the third day of part of 17.6 inches that fell through the 20th which was 94% of the month's total of 18.8 inches.

Bill of Rights day is today. Christmas Eve is in nine days and Christmas Day is in ten days. -Bernie-