February 16: ORD

Today is February 16th. It's the 47th day of the year. 319 days remain. It's week 7 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 36 and the normal low is 20. I've calculated the 33-year averages at 34 and 19.

On the warm side, in 1981 the high was 52 (O'Hare's only 50s high of the date) with a low of 38. Last year, in 2011, the high was 49 with a low of 37. In 1998 the high was 44 with the record-tying warmest low of 39, a spread of five degrees. The record warmest low of 39 first occurred in 1927, at a time when the official readings were taken adjacent to Lake Michigan. In 1984 the high was 46 with a low of 36. There were four other warm lows: two were 33 degrees (1982 & 1983) and two were 32 degrees (1992 & 2002). The record high of 58 was set in 1921, at a time when the official readings were taken adjacent to Lake Michigan. 30 of the past 33 highs (91%) were in the: 20s (8), 30s (15) and 40s (7). Our most recent 20s high was 27 in 2004. On the warm side, one high was in the 50s. On the cold side, two highs were in the 10s (a.k.a. teens). O'Hare's coldest highs were 15 degrees, first in 1967 and again in 1978. O'Hare's other pre-1979 10s high was 18 in 1973.

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 15 with a low of 2, a cold day. In 1977 the high was 26 with a cold low of 7 degrees, a cold day. In 1976 the low was a warm 34 degrees. In 1975 the high was 35 with a warm low of 32, a three degree spread. In 1973 the high was 18 with a low of 4, a cold day. In 1968 the high was 47 with a low of 14, a 33 degree spread. In 1967 the high was 15 with a low of 5, a cold day. In 1963 the high was 29 with a cold low of -5, a 34 degree spread and cold day. In 1962 the high was 34 with a low of 30, a four degree spread. In 1960 the high was 36 with a low of 29, a seven degree spread.

More recently, there were small spreads of four degrees on three occasions: 1982 (37/33), 1983 (37/33) and 1992 (36/32). There were two spreads of seven degrees: 2005 (33/26) and two years ago, in 2010 (32/25).

On the cold side, in 2007 the high was 19 with a low of -4. In 1980 the high was 17 with a low of 2. In the prior year, 1979, the high was 20 with a low of 9. In 2004 the high was 27 with a low of 5. In 1991 the high was 31 with a low of 1, a spread of 30 degrees. The other cold lows were 5 in 2008, 8 in 1985 and 8 in 1989. The record low of -10 was set way back in 1885 and the record coldest high of 2 was set way back in 1900. Both records were set at a time when the official readings were taken adjacent to Lake Michigan. 18 of the last 33 lows (55%) were in the: single digits (7) and 10s (a.k.a. teens) (11). Even colder, one low (3%) was in the negative single digits. (-4 in 2007). O'Hare's coldest low was -5 in 1963. On the warm side, 14 lows (42%) were in the: 20s (5) and 30s (9).

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 1980 the high was 17 with a low of 2, overall 18.5 degrees BELOW normal. Then in 1981 the high was 52 with a low of 38, overall 17 degrees ABOVE normal.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:20 and sunrise is at 6:49. Sunset is at 17:27 and twilight ends at 17:55. There's a total of 10 hours, 38 minutes of daylight today and 11 hours, 35 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:19 and sunrise is at 6:47. The moon is waning crescent, having reached last quarter two days ago at 11:04. Illumination was 33% at midnight, will be 28% at noon and 23% at midnight tonight. Moonrise is at 2:48 this morning. Moonset is at 12:14 this afternoon. Moonrise is at 3:42 tomorrow morning. Moonlight time is 9 hours, 26 minutes which is four minutes shorter than yesterday. Moonlight time is at it's least yesterday and today.

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. President's Day is in four days.