December 10: ORD

Today is December 10th. It's the 345th day of the year. 21 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 36 and the normal low is 22. The 30-year averages are 38 and 23.

On the warm side, in 1979 the high was 56 with a low of 31. In 2003 the high was 53 with a low of 29. A year later, in 2004, the high was 45 with a low of 37. Other warm highs were 51 in 1993, 49 in 1991, 48 in 2001 and 48 in 1990. Another warm low was 33 in 1997. I say "warm" but that's just because this low is above freezing. The record high of 62 was set way back in 1879. The record warmest low of 46 was set back in 1911. 23 of the 30 highs were 30s (13) and 40s (10). Three highs each were 20s and 40s. 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 8 with a low of -7, a cold day. The high of 8 tied the record coldest high of 8 set in 1919, but O'Hare in 1977 was not the official station of record for Chicago. In 1976 the high was 40 with a low of 7, a 33 degree spread. In 1972 the high was 15 with a low of -6, a cold day. In 1967 the high was 38 with a low of 36, a two degree spread. In 1962 the high was 18 with a low of 4, a cold day. In 1958 the high was 12 with a low of -8, a cold day.

More recently, we had small spreads of three degrees in 1997 (36/33), four degrees in 1992 (34/30), seven degrees in 1985 (37/30) and seven degrees last year (32/25).

On the cold side, in 1978 the high was 21 with the record low of -10, a very cold day. In 1995 the high was 14 with a cold low of 0. In 1986 the high was 20 with a cold low of 9. Two years later, in 1988, the high was 28 with a cold low of 8. Other cold lows were 9 in 1983 and 12 in 2005. The record coldest high of 8 was set back 1919. 22 of the last 30 lows were 20s (12) and 30s (10). Three lows were 10s, four lows were 0s, no lows were -0s but we had that one low in the -10s, indeed -10 in 1978.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:40 and sunrise is at 7:12. Chicago's twilight and sunrise times are four minutes earlier. Sunset is at 16:21 and twilight ends at 16:53. Chicago's sunset is a minute earlier and twilight ends two minutes earlier. There's a total of 9 hours, 9 minutes of daylight today and 10 hours, 13 minutes between twilights. Tomorrow twilight begins at 6:41 and sunrise is at 7:12. The moon is waxing gibbous. Illumination was 91% at midnight, will be 94% at noon and 97% at midnight tonight. Moonset was at 4:51 and moonrise is at 14:19. Moonset is at 6:11 tomorrow. Moonlight time is 14 hours, 32 minutes today.

Today is a major snow day in O'Hare's history. In 2000, 0.1 inches fell. This was the first day of a two day storm of 9.6 inches. In 1934 at the National Weather Service's former headquarters at the University of Chicago, 10.9 inches fell today.

A sister of mine, Regina, will celebrate a birthday in four days and Bill of Rights day is in five days. Christmas Eve is in two weeks and Christmas Day is in 15 days. -Bernie-