February 7: ORD

Today is February 7th. It's the 38th day of the year. 328 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 31 and 17.

On the warm side, three years ago, in 2009, the high was 56 with a low of 36 (O'Hare's warmest low of the date). In 1987 the high was 51 with a low of 31. These two 50s highs were the only ones in O'Hare's history. 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. The record high of 59 was set back in 1925, at a time when the official readings were taken adjacent to Lake Michigan. The record warmest low of 39 occurred in 1965 at Midway. 22 of the past 33 highs (67%) were in the: 20s (11) and 30s (11). O'Hare had seven consecutive 20s & 30s highs from 1978 through 1984. Six of these seven (86%) were in the 20s. On the warm side, seven highs (21%) were in the: 40s (5) and 50s (2). On the cold side, four highs (12%) were in the 10s (a.k.a. teens). O'Hare's coldest high was 7 in 1972.

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 a cold 21 degrees. In 1977 the high was 17 with a low of -10, a cold day. In 1975 the high was 26 with a cold low of -1, a cold day. In 1972 the high was 7 with a low of -12, a cold day. In 1971 the high was a cold 21 degrees. In 1970 the high was 37 with a warm low of 31, a six degree spread. In 1969 the high was 35 with a warm low of 30, a five degree spread. In 1968 the high was 30 with a low of 25, a five degree spread. In 1967 the high was 21 with a low of -2, a cold day. In 1965 the high was 48 with a low of 35, a warm day and year of the record warmest low of 39. In 1962 the high was 21 with a low of -2, a cold day. In 1961 the low was a cold 6 degrees. In 1960 the high was 30 with a low of 26, a four degree spread.

More recently, there were small spreads of three degrees in 2008 (27/24), six degrees in 1986 (29/23) and seven degrees in 1997 (29/22).

On the cold side, in 2007 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. The other cold high was 20 in 1995. The record low of -10 was set way back in 1875 and the record coldest high of 0 occurred way back in 1893. Both records occurred at a time when the official readings were taken adjacent to Lake Michigan. 25 of the last 33 lows (76%) were in the: single digits (8), 10s (a.k.a. teens) (7) and 20s (10). O'Hare had eight consecutive 0s, 10s and 20s lows from 1997 through 2004, only one of which was in the single digits (our most recent single digit low of 8 in 2003). On the cold side, three lows (9%) were in the negative single digits. O'Hare's coldest lows were -12 in 1972 and -10 in 1977. On the warm side, five lows (15%) were in the 30s. O'Hare's warmest low (until 2009) was 35 in 1965.

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In in 1989 the high was 21 with a low of 2, overall 13.5 degrees BELOW normal. Then in 1990 the high was 42 with a low of 33, overall 12.5 degrees ABOVE normal.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:31 and sunrise is at 7:00. Sunset is at 17:15 and twilight ends at 17:44. There's a total of 10 hours, 15 minutes of daylight today and 11 hours, 13 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:30 and sunrise is at 6:59. The moon is full today as the full Snow (a.k.a. Hunger) moon at 15:54. Illumination was 99% at midnight, will be 100% at noon and 100% at midnight tonight. Moonset was at 6:28 this morning. Moonrise is at 17:27 this afternoon. Moonset is at 7:00 tomorrow morning. Moonlight time is 13 hours, 1 minute which is 36 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 five days. Valentine's Day is in seven days. Susan B. Anthony Day is in eight days.