February 6: ORD

Today is February 6th. It's the 37th day of the year. 329 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. 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 33 and the normal low is 18. I've calculated the 33-year averages at 30 and 16.

On the warm side, in 2005 the high was 47 with a low of 39 (O'Hare's warmest low of the date). In 1999 the high was 46 with a low of 33. In 1990 the high was 46 with a low of 30. Three years earlier, in 1987, the high was 48 with a low of 26. The other warm low was 32 in 1991. The record high of 57 was set way back in 1882 and the record warmest low of 42 was set way back in 1904. Both records were set at a time when the official readings were taken adjacent to Lake Michigan. 15 of the past 33 highs (46%) were in the 30s. On the warm side, seven highs (21%) were in the 40s. O'Hare's warmest high (and only 50s high) of the date is 53 in 1964. On the cold side, 11 highs (33%) were in the: single digits (3), 10s (a.k.a. teens) (4) and 20s (4). Another cold high, pre-1979, is 7 in 1962. Our most recent 20s high was 28 in 1997.

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 17 with a low of 2, a cold day. In 1977 the high was 15 with a low of -7, a cold day. In 1976 the high was a cold 17 with a low of 11, a six degree spread. In 1975 the low was a cold 4 degrees. In 1974 the high was 27 with a low of 22, a five degree spread. In 1973 the high was 42 with a warm low of 31, a warm day. In 1972 the low was a cold 2 degrees. In 1970 the high was 39 with a warm low of 33, a six degree spread. In 1969 the high was 31 with a warm low of 30, a one degree spread. In 1968 the high was a warm 46 degrees. In 1967 the high was a cold 20 with a low of 16, a four degree spread. In 1965 the high was 49 with a low of 38, a warm day. In 1964 the high was 53 with a low of 30, a warm day. In 1963 the high was a warm 46 with a low of 27, a warm day. In 1962 the high was 7 with a low of -5, a cold day. In 1960 the high was 33 with a warm low of 30, a three degree spread. In 1959 the high was 25 with a cold low of -4, a cold day.

More recently, there were small spreads of four degrees in 1997 (28/24), four degrees in 2004 (30/26), five degrees in 1991 (37/32), six degrees in 1993 (32/26) and six degrees two years ago, in 2010 (31/25). There were large spreads of 33 degrees in 1996 (34/1) and 34 degrees three years ago, in 2009 (42/8).

On the cold side, in 1982 the high was the record coldest high of 4 with the record low of -14. In 1989 the high was 8 with a low of -4. In 2007 the high was 10 with a low of -5. In 1988 the high was 8 with a low of -2. Four years before, in 1984, the high was 12 with a low of 3. A year later, in 1985, the high was 19 with a low of -1. A decade after that, in 1995, the high was 19 with a low of 3. In 1979 the high was 25 with a low of -3. Another cold low was 1 in 1996. 13 of the last 33 lows (39%) were in the 30s. 15 lows (46%) were in the cold: negative single digits (5), single digits (4) and 10s (a.k.a. teens) (6). Our most recent 10s low was 15 in 2003. O'Hare's pre-1979 below zero lows are -7 in 1977, -5 in 1962 and -4 in 1959. Even colder, one low (3%) was in the negative 10s (a.k.a. negative teens). On the warm side, four lows (12%) were in the 30s. Until 2005, O'Hare's warmest low was 38 in 1965.

There were two instances of back-to-back years in which temperatures were just about as opposite as they can be. In the first instance, in 1987 the high was 48 with a low of 26, overall 12 degrees ABOVE normal. Then in 1988 the high was 8 with a low of -2, overall 22 degrees BELOW normal. In the second instance (which came on the heels of the first instance), in 1989 the high was 8 with a low of -4, overall 23 degrees BELOW normal. Then in 1990 the high was 46 with a low of 30, overall 13 degrees ABOVE normal.

An interesting fact concerning what happened three years ago: The National Weather Service/Chicago reports that January 2009 was just the tenth January (in 137 years of record-keeping) that no temperature reached 40 degrees. The last time this happened was in 1985. This also occurred in 1982, 1979, 1977, 1976, 1920, 1918, 1912 and 1904. January 1977 was a bit worse, since the temperatures that year never got to the freezing mark (32 degrees).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:32 and sunrise is at 7:02. Sunset is at 17:14 and twilight ends at 17:43. There's a total of 10 hours, 12 minutes of daylight today and 11 hours, 11 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:31 and sunrise is at 7:00. The moon is waxing gibbous, heading towards the full Snow (a.k.a. Hunger) moon tomorrow at 15:54. Illumination was 97% at midnight, will be 98% at noon and 99% at midnight tonight. Moonset was at 5:54 this morning. Moonrise is at 16:17 this afternoon. Moonset is at 6:28 tomorrow morning. Moonlight time is 13 hours, 37 minutes which is 28 minutes shorter than yesterday.

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. Abraham Lincoln's Birthday is in six days. Valentine's Day is in eight days. Susan B. Anthony Day is in nine days.