February 2: ORD

Today is February 2nd. It's the 33rd day of the year. 333 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. Before this, the official site was on the south side of Chicago at Midway International Airport (MDW), beginning on Wednesday, July 1, 1942. Before that, the official site was at various locations in Chicago going back to Monday, October 16, 1871. Observations taken from October 15, 1870 to October 8, 1871 were lost in the Great Chicago Fire.

According to the National Climatic Data Center (NCDC), the normal high is 32 and the normal low is 17. I've calculated the 33-year averages at 31 and 17.

On the warm side, in 1991 the high was 49 with a low of 30. Four years earlier, in 1987, the high was 50 with a low of 25. Five years later, in 1992, the high was the record high of 51 with a low of 24. These two 50s highs were the only ones in O'Hare's history for the date! In 1999 the high was 42 with a low of 33. Four years later, in 2003, the high was 39 with a low of 34 (our most recent 30s low), a five degree spread. That low of 34, along with the 34 degree low in 1973 were O'Hare's warmest lows of the date. In 1997 the high was 42 with a low of 29. The other warm high was 45 in 1984. The other warm lows were 32 in 1986, 31 in 1995 and 29 in 1990. The record warmest low of 38 was set way back in 1877, at a time when the official readings were taken adjacent to Lake Michigan. 26 of the past 33 highs (79%) were in the: 20s (7), 30s (13) and 40s (6). On the warm side, two highs were in the 50s. On the cold side, five highs were in the: negative single digits (1), single digits (1) and 10s (a.k.a. teens) (3).

In looking back through the years to the first February at O'Hare in 1959, the following instances were notable: In 1978 the high was 16 with a low of 3, a cold day. In 1977 the low was a cold 4 degrees. In 1976 the high was 7 with a low of -13, a cold day. In 1974 the high was 30 with a low of 28, a two degree spread. In 1973 the high was 46 with a low of 34, a warm day. In 1972 the high was 33 with a warm low of 29, a four degree spread. In 1971 the high was 18 with a low of -10, a cold day. In 1970 the high was 41 with a cold low of 1, a 40 degree spread. In 1967 the high was 27 with a low of 20, a seven degree spread. In 1965 the high was 0 with a low of -14, a cold day. In 1963 the high was 35 with a cold low of -1, a 36 degree spread. In 1961 the high was a cold 17 with a low of 11, a six degree spread. In 1960 the high was 29 with a low of 24, a five degree spread. In 1959 the high was 16 with a low of -9, a cold day.

More recently, there were small spreads of two degrees in 1990 (31/29), four degrees in 1995 (35/31), five degrees in 1986 (37/32), five degrees in 2008 (30/25), seven degrees in 1989 (28/21) and seven degrees two years ago, in 2010 (32/25).

On the cold side, in 1996 the high was the record coldest high of -5 with the record low of -16. In 1985 the high was 7 with a low of -11. In 2001 the high was 12 with a low of -2. In 2007 the high was 12 with a low of 6. In 1981 the high was 19 with a low of 0. A year earlier, in 1980, the high was 22 with a low of -3. The other cold low was 5 degrees last year, in 2011. 19 of the last 33 lows (58%) were in the: 10s (a.k.a. teens) (8) and 20s (11). On the cold side, nine lows (27%) were in the: negative 10s (a.k.a. negative teens) (2), negative single digits (2) and single digits (5). Prior to 1996, O'Hare's coldest lows of the date were -14 in 1965, -13 in 1976 and -10 in 1971. Five lows (15%) were in the warm 30s.

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 1996 the high was -5 with a low of -16, overall 34.5 degrees BELOW normal. Then in 1997 the high was 42 with a low of 29, overall 11.5 degrees ABOVE normal.

Today is a major day in O'Hare's snow history. Last year, 2011, was the start of a blizzard. It was the third of three days of the third biggest snowstorm in Chicago's history. A total of 21.2 inches fell at O'Hare and Rockford had 15.1 inches. O'Hare had 6.6 inches today and Rockford had 3.4 inches. This storm is famous for stranding many motorists on Lake Shore Drive in Chicago as its high winds created tall drifts.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:36 and sunrise is at 7:06. Sunset is at 17:08 and twilight ends at 17:38. There's a total of 10 hours, 2 minutes of daylight today and 11 hours, 2 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 6:35 and sunrise is at 7:05. The moon is waxing gibbous. Illumination was 69% at midnight, will be 74% at noon and 78% at midnight tonight. Moonset was at 2:50 this morning. Moonrise is at 12:17 this afternoon. Moonset is at 3:43 tomorrow morning. Moonlight time is 14 hours, 33 minutes which is 12 minutes longer than yesterday. Moonlight time is at its peak right now.

Winter began December 1st and runs for 102 days through March 11th. High temperatures in this period are usually in the 20s and 30s. Highs in the 40s and 50s occur infrequently. Groundhog Day is today. Lincoln's Birthday is in ten days.