December 16: ORD

Today is December 16th. It's the 351st day of the year. 15 days remain. It's week 51 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 35 and 22.

On the warm side, in 1984 the high was the record high of 60 with a low of 37. Two years ago the high was 55 with a low of 32. In 2001 the high was 45 with a low of 39, a six degree spread. In 1997 the high was 45 with a low of 32. Other warm highs were 43 in the back-to-back years of 2003 and 2004. Other warm lows were 32 in 1998; 33 in both 1990 and 1993. Lows were also 34 in 1994 and 35 in 1986. The record warmest low of 43 was set in 1928. 21 of the last 30 highs were 30s (13) and 40s (8). Five highs were 20s and one high each was in the 0s, 10s, 50s and 60s.

In looking back through the years to the first December at O'Hare in 1958, the following instances were notable. In 1974 the high was 36 with a low of 30, a six degree spread. In 1972 the high was 9 with a low of -2, a cold day. In 1971 the high was 39 with a low of 33, a six degree spread. In 1970 the high was 39 with a low of 36, a three degree spread. In 1966 the high was 34 with a low of 32, a two degree spread. In 1965 the high was 30 with a low of 24, a six degree spread. In 1963 the high was 15 with a low of -6, a cold day. In 1958 the high was 36 with a low of 0, a spread of 36 degrees and a cold day.

More recently, we had small spreads of three degrees in 1980 (33/30), three degrees in 1990 (36/33), three degrees in 2002 (33/30), five degrees in 1986 (40/35), five degrees in 1994 (39/34), six degrees in 1996 (32/26), six degrees in 2005 (24/18) and seven degrees in 1993 (40/33).

On the cold side, in 1989 the high was 9 with a low of -5. A year before, in 1988, the high was 17 with a low of 4. In 1985 the high was 23 with a low of 3. In 1983 the high was 23 with a low of 3. In 1981 the high was 22 with a low of 9. In these days you can see examples of the coldness of the decade of the 1980s. Other cold lows were 5 in 1979 and 6 in 1991. The record low of -12 and record coldest high of 2 occurred in 1951. 19 of the last 30 lows were 20s (7) and 30s (12). Among the colder lows, four were 10s, six were 0s and one was in the negative zeros.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:44 and sunrise is at 7:16. Chicago's twilight and sunrise times are three minutes earlier. Sunset is at 16:22 and twilight ends at 16:54. Chicago's sunset and end of twilight times are a minute earlier. There's a total of 9 hours, 6 minutes of daylight today and 10 hours, 10 minutes between twilights. Tomorrow twilight begins at 6:45 and sunrise is at 7:17. The moon is waning gibbous, heading towards the last quarter on Friday at 4:29. Illumination was 82% at midnight, will be 78% at noon and 73% at midnight tonight. Moonset is at 10:32 and moonrise is at 21:23. Moonlight time is 13 hours, 9 minutes today.

Today is a major snow day in O'Hare's history. In 1973, 4.5 inches fell. This was the fourth day of part of 17.6 inches that fell through the 20th which was 94% of the month's total of 18.8 inches.

Christmas Eve is in eight days and Christmas Day is in nine days. New Year's Eve is in 15 days and New Year's Day is in 16 days. -Bernie-