December 13: ORD

Today is December 13th. It's the 348th day of the year. 18 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 35 and the normal low is 21. The 30-year averages are 35 and 22.

On the warm side, in 1993 the high was 46 with a low of 35. Two years ago the high was 45 with a low of 33. In 2001 the high was 46 with a low of 31. Other warm highs were 49 in 1998 and 44 in 1991. The last time it hit 50 degrees or higher was in 1975 when it was 64 at O'Hare, 67 at Midway, 60 at Marengo and 57 at Rockford. Another warm low was 33 in 2002. The record high of 67 occurred in 1975 and the record warmest low of 46 was set in 1920. 16 of the last 30 highs were 30s, eight highs were 40s, five were 20s and one 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 36, a three degree spread. In 1975 the high was 64 with a low of 38, a bonus 60s day. The record high was 67 at Midway this day. In 1970 the high was 32 with a low of 25, a seven degree spread. In 1968 the high was 49 with a low of 18, a 31 degree spread. In 1966 the high was 29 with a low of 23, a six degree spread. In 1963 the high was 12 with a low of -2, a cold day. In 1962 the high was 20 with a low of 2, another cold day. In 1961 the high was 16 with a low of 1, yet another cold day. In 1958 the high was 12 with a low of -8, one last cold day!

More recently, we had small spreads of four degrees in 1983 (35/31), five degrees in 1984 (37/32), five degrees three years ago (28/23), six degrees in 2002 (39/33), six degrees last year (34/28) and seven degrees in 1981 (36/29).

On the cold side, in 1985 the high was 12 with a low of -3. In 2000 the high was 24 with a low of -8. In 1989 the high was 20 with a low of 6. In 1986 the high was 25 with a low of 1. The record low of -13 and record coldest high of 3 were both set in 1903. 15 of the last 30 lows were 20s, seven were 30s, four were 10s, two were zeros and two were negative zeros.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:42 and sunrise is at 7:14. Sunset is at 16:22 and twilight ends at 16:53. There's a total of 9 hours, 8 minutes of daylight today and 10 hours, 11 minutes between twilights. Tomorrow twilight begins at 6:43 and sunrise is at 7:15. The full Cold moon was yesterday at 10:37. Illumination was 99% at midnight, will be 98% at noon and 96% at midnight tonight. Moonset is at 8:30 and moonrise is at 17:27. Moonset is at 9:21 tomorrow. Moonlight time is 15 hours, 3 minutes today.

Today is a major snow day in O'Hare's history. In 1973, 4.0 inches fell. This was the first day of part of 17.6 inches that fell through the 20th which was 94% of the month's total of 18.8 inches.

A sister of mine, Regina, will celebrate a birthday tomorrow and Bill of Rights day is in two days. Christmas Eve is in 11 days and Christmas Day is in 12 days. -Bernie-