February 4: ORD

Today is February 4th. It's the 35th day of the year. 330 days remain. It's week 5 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 32-year averages are 29 and 14.

On the warm side, in 1991 the high was 51 with a low of 36. A couple of years later, in 1993, the high was 52 with a low of 24. Three years ago, in 2008, the high was 44 with a low of 32. Three years before, in 2005, the high was 50 with a low of 22. In 1992 the high was 40 with a low of 31. Other warm lows were 32 in 1986 and 31 (1997 and 1998). The record high of 59 was set way back in 1890 and the record warmest low of 37 was set way back in 1909. 16 of the last 32 highs (50%) were: 20s (6) and 30s (10). On the warmer side, eight highs (25%) were in the: 40s (5) and 50s (3). On the cold side, eight highs (25%) were in the: single digits (3) and 10s (a.k.a. teens) (5).

In looking back through the years to the first February at O'Hare in 1959, the following instances were notable: in 1978 the low was a cold 3 degrees. In 1975 the low was a warm 31 degrees. In 1973 the high was 50 with a low of 34, a warm day. In 1972 the high was 9 with a low of -2, a cold day. In 1971 the high was 48 with a low of 31, a warm day. In 1970 the high was 34 with a cold low of -1, a 35 degree spread. In 1969 the high was 42 with a low of 10, a 32 degree spread. In 1966 the high was 20 with a low of -3, a cold day. In 1965 the high was 15 with a low of -10, another cold day. In 1964 the high was a warm 47 degrees with a low of 17, a 30 degree spread. In 1962 the high was 50 with a low of 32, a warm day.

More recently, there were small spreads of two degrees in 1998 (33/31), five degrees in 1986 (37/32), six degrees in 1997 (37/31) and seven degrees in 2006 (32/25).

On the cold side, in 1996 the high was 2 with the record low of -14. In 2007 the high was 2 with a low of -6. In 1981 the high was 10 with a low of -4. In 1989 the high was 7 with a low of 1, a six degree spread. A decade earlier, in 1979, the high was 12 with a low of -2. In 1985 the high was 19 with a low of -7. Three years before, in 1982, the high was 18 with a low of -2. Two years ago the high was 17 with a low of 0. In 1983 the high was 20 with a low of 3. Another cold high was 20 in 1994. Another cold low was 0 in 2004. The record coldest high of 0 was set in 1918. 31 of the last 32 lows (97%) were in the: negative single digits (5), single digits (6), 10s (a.k.a. teens) (5), 20s (9) and 30s (6). Even colder, one low was in the negative 10s (a.k.a. negative teens). Through Winter 2009-10, this is the average seventh coldest day of the year.

Today is not a major day in Chicago's snow history. But I'll be writing about a snow event that took place in Rockford in a couple of days.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:34 and sunrise is at 7:04. Sunset is at 17:11 and twilight ends at 17:41. There's a total of 10 hours, 7 minutes of daylight today and 11 hours, 7 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 6:33 and sunrise is at 7:03. The moon is waxing crescent, having passed new two nights ago at 20:31. Illumination was 1% at midnight, will be 3% at noon and 4% at midnight tonight. Moonrise is at 7:29 this morning. Moonset is at 19:06 this afternoon. Moonrise is at 7:52 tomorrow morning. Moonlight time is 11 hours, 37 minutes which is 36 minutes longer than yesterday.

Lincoln's Birthday is in eight days. Valentine's Day is in ten days. Susan B. Anthony Day is in 11 days. -Bernie-