March 20: ORD

Today is March 20th. It's the 79th day of the year. 286 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 32-year averages at 47 and 30.

On the warm side, in 2003 the high was 65 with a low of 43. In 1994 the high was 61 with a low of 39. A year later, in 1995, the high was 60 with a low of 40. Other warm highs were 62 in 2004 and 61 in 1991. Another warm low was 43 in 2000. The record high of 76 was set back in 1921 and the record warmest low of 53 occurred back in 1918. Unusual for just three years of separation for these records. 20 of the last 32 highs (63%) were in the: 30s (8) and 40s (12). On the warmer side, 11 highs (34%) were in the: 50s (6) and 60s (5). Our most recent 50s high was 55 in 2000. On the cold side, one high was in the 20s. Today is the midrange (average of earliest and latest dates) date of our first high in the 70s, based upon the last 32 years.

In looking back through the years to the first March at O'Hare in 1959, the following instances were notable: In 1976 the high was 70 with a low of 47, a warm day. In 1975 the high was a warm 60 degrees. In 1972 the high was a warm 69 with a low of 38, a 31 degree spread and warm day. In 1970 the high was 41 with a low of 36, a five degree spread. In 1967 the high was a cold 36 with a low of 33, a three degree spread. In 1966 the high was 56 with a low of 26, a 30 degree spread. In 1965 the high was 22 with a low of 0, a cold day. In 1960 the high was a cold 34 with a low of 20, a cold day.

More recently, we had small spreads of three degrees in 1998 (36/33), five degrees in 1983 (32/27) and seven degrees in 1993 (38/31). There was a large spread of 30 degrees in 2004 as the high was 62 with a low of 32.

On the cold side, in 1986 the high was 26 with a low of 8. Two years later, in 1988, the high was 36 with a low of 20. Other cold highs were 32 in 1983 and 36 in 1998. The record low of 4 and record coldest high of 15 were set on the same cold day way back in 1885. 28 of the last 32 lows (88%) were in the: 20s (15) and 30s (13). One low was in the cold single digits. Three lows were in the warmer 40s. No lows have been in the 10s (a.k.a. teens) over the last 32 years.

Today is a major day in Chicago's snow history. At O'Hare in 1965, this was the first of seven days in which a total of 10.2 inches fell. Today just a tenth of an inch fell. At O'Hare in 1983, this was the second day of a three day, 7.2 inch snowstorm. Today 3.3 inches fell.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:29 and sunrise is at 6:57. Sunset is at 19:05 and twilight ends at 19:33. There's a total of 12 hours, 8 minutes of daylight today and 13 hours, 4 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:27 and sunrise is at 6:55. The moon is waxing gibbous and reached full yesterday at 13:10. It's the full Worm or Sap moon. Illumination was 99% at midnight, will be 98% at noon and 96% at midnight tonight. Moonset is at 7:00 this morning. Moonrise is at 20:48 tonight. Moonset is at 7:34 tomorrow morning. Moonlight time is 10 hours, 12 minutes which is 48 minutes shorter than yesterday. The Spring Equinox is today at 18:21.

April Fool's Day is 12 days. The warm part of Spring (Warm Spring) begins in 24 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-