February 20: ORD

Today is February 20th. It's the 51st day of the year. 315 days remain. It's week 8 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. ORD has been the official site of record for Chicago 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 37 and the normal low is 22. I've calculated the 33-year averages at 41 and 24.

On the warm side, in 1983 O'Hare had its warmest February 20th: a high of 61 (O'Hare's only 60s high of the date) with a low of 36 (O'Hare's warmest low of the date). In 1994 the high was 57 with a low of 33. In 2002 the high was 54 with a low of 34. In 1996 the high was 53 with a low of 34. The year earlier, in 1995, the high was 50 with a low of 31. The other warm high was 50 in 2003 (our most recent 50s high). The other warm lows were 35 in both 1980 and 1998. The record high of 64 and record warmest low of 49 were set on the same warm day back in 1930, at a time when the official readings were taken adjacent to Lake Michigan. 25 of the past 33 highs (76%) were in the: 30s (13) and 40s (12). O'Hare registered ten consecutive highs in the 30s & 40s from 1984 through 1993. On the warm side, six highs (18%) were in the: 50s (5) and 60s (1). O'Hare's pre-1979 50s highs were 56 in 1976 and 51 in 1965. On the cold side, two highs (6%) were in the 10s (a.k.a. teens) (1) and 20s (1). O'Hare's coldest high was 17 in 1966.

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 26 with a cold low of 8, a cold day. In 1976 the high was a warm 56 with a low of 28, a warm day. In 1974 the high was a warm 49 degrees. In 1973 the high was 36 with a low of 30, a six degree spread. In 1970 the high was 20 with a low of 5, a cold day. In 1968 the high was 24 with a low of 7, a cold day. In 1967 the low was a cold 8 degrees. In 1966 the high was 17 with a low of -5, a cold day. In 1965 the high was a warm 51 degrees. In 1963 the high was 30 with a cold low of -2, a 32 degree spread and cold day. In 1962 the high was 24 with a low of 8, a cold day. In 1960 the high was 29 with a cold low of 4, a cold day. In 1959 the high was 21 with a low of -3, a cold day.

More recently, there were small spreads of six degrees on three occasions: in 1980 (41/35), 1989 (30/24) and 2005 (37/31). There was a spread of seven degrees in 1998 (42/35). There was a large spread of 30 degrees in 1987 (47/17).

On the cold side, in 2008 the high was 19 with a low of 5. The year later (three years ago), in 2009, the high was 28 with a low of 12. In 1990 the high was 33 with a low of 7. The other cold low was 8 in 1988. The record low of -9 and record coldest high of 7 were set on the same cold day way back in 1896, at a time when the official readings were taken adjacent to Lake Michigan. 30 of the last 33 lows (91%) were in the: 10s (a.k.a. teens) (8), 20s (8) and 30s (14). Three lows were in the cold single digits. O'Hare's coldest low of the date was -5 in 1966. Along with a high of 17, 1966 was O'Hare's coldest February 20th. O'Hare also had sub-zero lows of -3 in 1959 and -2 in 1963.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:15 and sunrise is at 6:43. Sunset is at 17:32 and twilight ends at 18:00. There's a total of 10 hours, 49 minutes of daylight today and 11 hours, 45 minutes between twilights. We gained four minutes of daylight from yesterday. Tomorrow twilight begins at 6:13 and sunrise is at 6:42. The moon is waning crescent and will be new tomorrow at 16:35. Illumination was 3% at midnight, will be 2% at noon and 1% at midnight tonight. Moonrise is at 5:41 this morning. Moonset is at 16:36 this afternoon. Moonrise is at 6:10 tomorrow morning. Moonlight time is 10 hours, 55 minutes which is 32 minutes longer 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. Presidents' Day is today. Mardi Gras is tomorrow. George Washington's Birthday and Ash Wednesday are in two days.