Sunday, March 15, 2009

March 15: ORD

Today is March 15th. It's the 74th day of the year. 291 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 46 and the normal low is 28. I've calculated the 30-year averages at 46 and 27.


On the warm side, in 1995 the high was the record high of 74 with a low of 43, a 31 degree spread. Five years earlier, in 1990, the high was 68 with a low of 45. In 2000 the high was 65 with a low of 34, a 31 degree spread. Other warm highs were 62 in 1981 and 59 in 2002. The record warmest low of 49 was set back in 1945.
12 of the last 30 highs were 40s. On the warmer side, nine high were: 50s (5), 60s (3) and 70s (1). On the colder side, nine highs were: 30s (7) and 20s (2).

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 36 with a low of 31, a five degree spread. In 1977 the high was 71 with a low of 44, a bonus 70s day. In 1968 the high was 60 with a low of 39, a bonus 60s day. In 1962 the high was 28 with a low of 21, a seven degree spread.

More recently, we had small spreads of six degrees in 1987 (38/32), seven degrees in 1982 (43/36) and seven degrees in 1986 (41/34). Other large spreads were 34 degrees in 1993 (47/13) and 32 degrees in 1981 (62/30).

On the cold side, in 1997 the high was 26 with a low of 13. In 1979 the high was 25 with a low of 15. In 1988 the high was 30 with a low of 17. Another cold low was 13 in 1993. Another cold high was 32 in 1998. The record low of 6 occurred way back in 1890. The record coldest high of 17 was set way back in 1893. 15 of the last 30 lows were 20s. Four lows were on the colder 10s (a.k.a. teens). On the warmer side, 11 lows were: 30s (9) and 40s (2).

Today is a not a major day in Chicago's snow history.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 6:37 and sunrise was at 7:05. Sunset is at 19:00 and twilight ends at 19:28. Tomorrow twilight begins at 6:35 and sunrise is at 7:03. There's a total of 11 hours, 55 minutes of daylight today and 12 hours, 51 minutes between twilights. The moon is waning gibbous. Illumination was 81% at midnight, will be 77% at noon and 73% at midnight tonight. Moonset was at 8:55. Tomorrow moonrise is at 0:34 and moonset is at 9:32. Moonlight time is 8 hours, 55 minutes which was 1 minute longer than yesterday.

St. Patrick's Day is in two days. -Bernie-

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