February 7: ORD

Today is February 7th. It's the 38th day of the year. 327 days remain. It's week 6 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. I've calculated the 30-year averages at 30 and 16.

On the warm side, in 1987 the high was 51 with a low of 31. In 2005 the high was 45 with a low of 33. In 1996 the high was 44 with a low of 32. Six years earlier, in 1990, the high was 42 with a low of 33. Today we've been in the 50s. It's been 22 years since that's last happened. What's more rare, I don't see any 50s highs at O'Hare since it's first February in 1959 through 1978. So this is just the second occurrence. The record high of 59 was set back in 1925 and the record warmest low of 39 was set in 1965. 20 of the last 30 highs were: 20s (11) and 30s (9). On the warmer side, six highs were: 40s (5) and 50s (1). On the colder side, four highs were 10s (a.k.a. teens).

In looking back through the years to the first February at O'Hare in 1959, the following instances were notable: In 1977 the high was 17 with a low of -10, a cold day. In 1975 the high was 26 with a low of -1, a cold day. In 1972 the high was 7 with a low of -12, a cold day. In 1970 the high was 37 with a low of 31, a six degree spread. In 1969 the high was 35 with a low of 30, a five degree spread. In 1968 the high was 30 with a low of 25, another five degree spread. In 1967 the high was 21 with a low of -2, another cold day. In 1962 the high was 21 with a low of -2, yet another cold day. In 1960 the high was 30 with a low of 26, a four degree spread.

More recently, there were small spreads of three degrees last year (27/24), six degrees in 1986 (29/23) and seven degrees in 1997 (29/22).

On the cold side, two years ago the high was 11 with a low of -2. In 1985 the high was 19 with a low of -2. In 1979 the high was 20 with a low of -3. In 1994 the high was 17 with a low of 6. Five years before that, in 1989, the high was 21 with a low of 2. Five years before that, in 1984, the high was 22 with a low of 1. A couple of years before that, in 1982, the high was 21 with a low of 2. In 2003 the high was 18 with a low of 8. Another cold high was 20 in 1995. 23 of the last 30 lows have been: single digits (8), 10s (a.k.a. teens)(6) and 20s (9). Even colder, three lows have been in the negative single digits. On the warmer side, four lows were in the 30s.

Since today is not a major day in Chicago's snow history, I wanted to post an exchange I found on the WGN-TV web log. The answer was given by meteorologist Tom Skilling. It concerns Chicago's 18 below zero temperatures. The question asked by Paul Rubin was, "The lowest temperature so far this winter has been 18 degrees below zero. That seems colder than we usually get in the winter here in Chicago. How many winters have had a lower temperature than 18 below?" The answer was, "Your hunch is correct. A computer scan of Chicago's entire official temperature data set (138 years of records from the winter of 1870-71 to the present) reveals that only 12 winters have produced a reading lower than the temperature of 18 degrees below zero recorded here on Jan. 16. And that was the city's lowest temperature in 13 years -- since 19 below zero on Feb. 3, 1996. On average, the coldest temperature recorded during the winter at O'Hare Airport is 11 degrees below zero. Over the last ten years, however, with relatively mild winters, the lowest temperatures each winter have averaged only 6 below zero."

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 6:30 and sunrise was at 7:00. Sunset is at 17:16 and twilight ends at 17:45. There's a total of 10 hours, 16 minutes of daylight today and 11 hours, 15 minutes between twilights. Tomorrow twilight begins at 6:29 and sunrise is at 6:58. The moon is waxing gibbous. Illumination was 92% at midnight, will be 95% at noon and 97% at midnight tonight. Moonset was at 5:41. Moonrise was at 15:04. Moonset is at 6:21 tomorrow. Moonlight time is 14 hours, 37 minutes which is 29 minutes shorter than yesterday.

Abraham Lincoln's Birthday is in five days. Valentine's Day is in a week. The Daytona 500 is in a week and a day. President's Day is in a week and two days. -Bernie-