March 6: ORD

Today is March 6th. It's the 65th day of the year. 300 days remain. It's week 10 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 42 and the normal low is 25. I've calculated the 32-year averages at 42 and 25.

On the warm side, in 1983 the high was the co-record high of 70 with the record warmest low of 53. In 1992 the high was 62 with a low of 47. Two years ago, in 2009, the high was 65 with a low of 39. In 2000 the high was the co-record high of 70 with a low of 32, a 38 degree spread. Five years later, in 2005, the high was 64 with a low of 35. In 1994 the high was 58 with a low of 39. In 1987 the high was 67 with a low of 29, a 38 degree spread. Another warm low was 37 in 2004. 14 of the last 32 highs (44%) were in the 30s. On the warmer side, 13 highs (41%) were in the: 40s (4), 50s (3), 60s (4) and 70s (2). On the cold side, five highs (16%) were in the 20s.

In looking back through the years to the first March at O'Hare in 1959, the following instances were notable: In 1974 the high was 59 with a low of 42, a warm day. In 1973 the high was 64 with a low of 39, another warm day. In 1972 the high was 49 with a cold low of 12, a 37 degree spread. In 1969 the high was 39 with a low of 32, a seven degree spread. In 1966 the high was a cold 27 with a low of 21, a six degree spread. In 1965 the high was 33 with a low of 31, a two degree spread. In 1964 the high was a warm 55 with a low of 22, a 33 degree spread. In 1960 the high was 20 with a low of -1, year of the record low of 2 and a very cold day.

More recently, we had small spreads of four degrees in 1995 (35/31) and six degrees in 1990 (32/26). Another large spread was 30 degrees in 1988 (51/21).

On the cold side, in 1982 the high was 24 with a low of 4. Two years earlier, in 1980, the high was 28 with a low of 6. In 2003 the high was 28 with a low of 11. Four years later, in 2007, the high was 24 with a low of 16. In 1996 the high was 30 with a low of 11. In 1984 the high was 27 with a low of 14. Other cold highs were 30 in both 1989 and a decade later in 1999. The record low of 2 was set in 1960 and the record coldest high of 15 was set back in 1932. 16 of the last 32 lows (50%) were in the 20s. Eight lows were in the cold: 10s (a.k.a. teens) (6) and single digits (2). Eight lows (25%) were in the warmer: 30s (6), 40s (1) and 50s (1).

Today is a major day in Chicago's snow history. In 1999, 1.6 inches fell. This was the second of six days in which a total of 18.2 inches fell.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:53 and sunrise is at 6:21. Sunset is at 17:49 and twilight ends at 18:17. There's a total of 11 hours, 28 minutes of daylight today and 12 hours, 24 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 5:51 and sunrise is at 6:19. The moon passed new two afternoons ago at 14:46 and is waxing crescent. Illumination was 2% at midnight, will be 3% at noon and 5% at midnight tonight. Moonrise is at 6:42 this morning. Moonset is at 19:56 tonight. Moonrise is at 7:05 tomorrow morning. Moonlight time is 13 hours, 14 minutes which is 36 minutes longer than yesterday.

Mardi Gras is in two days. Ash Wednesday is in three days. The cool part of Spring (Cool Spring) begins in six days on March 12. Cool Spring runs for 32 days, through April 12. High temperatures in this period are usually in the 30s, 40s and 50s. Warmer 60s and 70s occur infrequently. -Bernie-