March 13: ORD

Today is March 13th. It's the 72nd day of the year. 293 days remain. It's week 11 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 44 and the normal low is 28. I've calculated the 32-year averages at 46 and 30.

On the warm side, in 1990 the high was 72 (a former record high) with the record warmest low of 62. Five years later, in 1995, the high was 72 (another former record high) with a low of 51. In 2007 the high was the record high of 73 with a low of 48. Five years before, in 2002, the high was 59 with a low of 36. Other warm highs were 63 in 2006, 58 in 1996, 57 three years ago (in 2008) and 56 in 1986. 27 of the last 32 highs (84%) were in the: 30s (11), 40s (8) and 50s (8). On the warmer side, four highs were in the: 60s (1) and 70s (3). On the cold side, one high was in the 20s.

In looking back through the years to the first March at O'Hare in 1959, the following instances were notable: In 1978 the high was 37 with a low of 31, a six degree spread. In 1977 the high was 50 with a warm low of 43, a seven degree spread. In 1975 the high was 31 with a low of 16, a cold day. In 1973 the high was a warm 62 with a low of 34, a warm day. In 1972 the high was 37 with a low of 30, a seven degree spread. In 1968 the low was a cold 13 degrees. In 1967 the high was 40 with a low of 35, a five degree spread. In 1964 the high was a warm 59 degrees. In 1962 the high was 34 with a low of 29, a five degree spread. In 1961 the high was 42 with a low of 35, a seven degree spread. In 1960 the high was a cold 28 with a low of 17, a cold day.

More recently, we had small spreads of four degrees last year (in 2010) (45/41), six degrees in 1985 (38/32), six degrees in 1987 (37/31) and seven degrees in 1991 (36/29). The other large spreads were 31 degrees in 1983 (54/23) and 33 degrees in 2006 (63/30).

On the cold side, in 1993 the high was 22 with a low of 11. In 2005 the high was 33 with a low of 13. Other cold highs were 31 in 1988 and 32 in 1980. The record low of 6 was set way back in 1896. The record coldest high of 21 occurred way back in 1888. 14 of the last 32 lows (44%) were in the 30s. 14 lows (44%) were on the cold side: 10s (a.k.a. teens) (7) and 20s (7). On the warmer side, four lows (12%) were in the: 40s (2), 50s (1) and 60s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:41 and sunrise is at 7:09. Sunset is at 18:57 and twilight ends at 19:25. There's a total of 11 hours, 48 minutes of daylight today and 12 hours, 44 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:40 and sunrise is at 7:07. The moon is waxing gibbous and reached first quarter yesterday at 17:45. Illumination was 53% at midnight, will be 58% at noon and 63% at midnight tonight. Moonset was at 2:58 this morning. Moonrise is at 12:05 this afternoon. Moonset is at 3:35 tomorrow morning. Moonlight time is 14 hours, 43 minutes which is four minutes shorter than yesterday.

St. Patrick's Day is in four days. The warm part of Spring (Warm Spring) begins in 31 days on April 13. Warm Spring runs for 52 days, through June 3. High temperatures in this period are usually in the 50s, 60s and 70s. Warmer 80s and 90s occur infrequently. -Bernie-