March 21: ORD

Today is March 21st. It's the 80th day of the year. 285 days remain. It's week 12 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.

According to the National Climatic Data Center (NCDC), the normal high is 48 and the normal low is 30. I've calculated the 31-year averages at 46 and 29.

On the warm side, in 1991 the high was 71 with a low of 49. Six years later, in 1997, the high was 71 with a low of 36, a 35 degree spread. A decade later, in 2007 (three years ago), the high was 67 with a low of 37, a 30 degree spread. Other warm highs were 63 in 1990, 61 last year and 60 in 1987. Another warm low was 42 in 2000. The record high of 77 was set back in 1938 and the record warmest low of 54 was set back in 1918. 21 of the last 31 highs were: 30s (12) and 40s (9). On the warmer side, ten highs were: 50s (4), 60s (4) and 70s (2).

In looking back through the years to the first March at O'Hare in 1959, the following instances were notable: In 1977 the high was 38 with a low of 33, a five degree spread. In 1975 the high was a warm 70 with a low of 41, a warm day. In 1972 the high was 62 with a low of 42, a warm day. In 1970 the high was 59 with a low of 29, a 30 degree spread. In 1967 the high was 38 with a low of 31, a seven degree spread. In 1966 the high was 67 with a low of 42, a warm day. In 1965 the high was 21 with a low of 8, the coldest day ever at O'Hare for March 21st. In 1962 the high was 39 with a low of 32, a seven degree spread. In 1960 the high was 35 with a low of 10, a cold day.

More recently, we had small spreads of four degrees in 1984 (35/31), five degrees in 1982 (40/35) and five degrees two years ago (34/29). There were large spreads of 31 degrees in 1990 (63/32) and 32 degrees in 1987 (60/28).

On the cold side, in 1986 the high was 37 with a low of 13. Three years before, in 1983, the high was 30 with a low of 21. In 2004 the high was 33 with a low of 22. Another cold low was 17 in 2002. Other cold highs were 33 in 2006, 34 two years ago, 35 (1984, 1988, 1989), and 36 in 1992. The record low of 9 was set way back in 1888 and record coldest high of 19 was set way back in 1885. 27 of the last 31 lows were: 20s (15) and 30s (12). Two lows were in the colder 10s (a.k.a. teens) and two lows were in the warmer 40s.

Today is a major day in Chicago's snow history. At O'Hare in 1965, this was the second of seven days in which a total of 10.2 inches fell. Today just three tenths of an inch fell. In 1932 in Rockford, 11 inches fell. At the University of Chicago in 1932, a total of 8.9 inches fell from March 20-22. 7.8 inches of the total fell today, on the 21st. Two years ago was the first day of a two-day storm. At O'Hare, 4.8 inches fell. Rockford had 4.7 inches and Midway had 2.6 inches. Some of Midway's precipitation was a wintry mix (freezing rain, sleet).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 6:27 and sunrise was at 6:55. Sunset is at 19:07 and twilight ends at 19:35. There's a total of 12 hours, 12 minutes of daylight today and 13 hours, 8 minutes between twilights. Tomorrow twilight begins at 6:25 and sunrise is at 6:53. The moon is waxing crescent. Illumination was 27% at midnight, will be 32% at noon and 37% at midnight tonight. Moonset was at 0:34 this morning. Moonrise is at 9:41. Moonset is at 1:37 early tomorrow morning. Moonlight time is 14 hours, 53 minutes which is 11 minutes shorter than yesterday. -Bernie-