December 25: ORD

Today is December 25th. It's the 359th day of the year. Six days remain. It's week 52 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 32 and the normal low is 17. The 31-year averages are 29 and 13.

On the warm side, in 1982 the high was the record high of 64 with a low of 36. In 1994 the high was 52 with a low of 24. Other warm lows were 33 in 2005, 30 three years ago, 29 in 1987 and 28 in 1979. The record warmest low of 46 occurred in 1936. 24 of the last 31 highs were 10s (5), 20s (7) and 30s (12). On the warmer side, two highs were 40s, one was in the 50s and one was in the 60s. On the colder side, two highs were single digits and one high was in the negative single digits.

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 14 with a low of -2, a cold day. In 1975 the high was 36 with a low of 31, a five degree spread. In 1973 the high was 40 with a low of 37, a three degree spread and warm day. In 1972 the high was 35 with a low of 31, a four degree spread. In 1971 the high was 45 with a low of 30, a warm day. In 1969 the high was 28 with a low of 21, a seven degree spread. In 1968 the high was 18 with a low of 0, a cold day. In 1964 the high was 27 with a low of 23, a four degree spread.

More recently, we had small spreads of three degrees in 2005 (36/33), six degrees in 1986 (32/26), six degrees in 2002 (29/23), seven degrees in 1987 (36/29) and seven degrees three years ago (37/30).

On the cold side, in 1983 the high was the record coldest high of -5 with the record low of -17. Two years later, in 1985, the high was 2 with a low of -11. Five years earlier, in 1980, the high was 17 with a low of -8. Two decades later, in 2000, the high was 17 with a low of -7. Four years before that, in 1996, the high was 9 with a low of 1. A dozen years before that, in 1984, the high was 19 with a low of -3. In 1993 the high was 18 with a low of 5. Last year the high was 24 with a low of 0. In 1990 the high was 28 with a low of -1. Another cold high was 19 in 2004. 18 of the last 31 lows were: 10s (11) and 20s (7). On the colder side, four lows were single digits, four lows were negative single digits and two lows were negative 10s (aka negative teens). On the warmer side, three lows were in the 30s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:49 and sunrise is at 7:21. Sunset is at 16:27 and twilight ends at 16:59. There's a total of 9 hours, 6 minutes of daylight today and 10 hours, 10 minutes between twilights. Tomorrow twilight begins at 6:49 and sunrise is at 7:21. The moon is waxing gibbous, having reached first quarter yesterday at 11:36. Illumination was 55% at midnight, will be 60% at noon and 65% at midnight tonight. Moonset was at 36 minutes past midnight. Moonrise is at 12:12. Moonset is at 1:42 early tomorrow morning. Moonlight time is 12 hours, 51 minutes which is 13 minutes longer than yesterday.

Today is not a major snow day in O'Hare's history. The next one is in a couple of days and it occurred way back in 1894! Christmas Day is today, New Year's Eve is in six days and New Year's Day is in seven days. -Bernie-