March 18: ORD

Today is March 18th. It's the 77th day of the year. 288 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 47 and the normal low is 29. I've calculated the 32-year averages at 45 and 29.

On the warm side, in 1979 the high was 70 with a low of 43. Last year, in 2010, the high was 61 with a low of 41. In 1995 the high was 66 with a low of 34, a 32 degree spread. Two years ago, in 2009, the high was 57 with a low of 42. Another warm high was 59 in 1986. The record high of 74 was originally set in 1903 and tied in both 1918 and 1969. The record warmest low of 59 occurred way back in 1894. 18 of the last 32 highs (56%) were in the 40s. There were ten straight 40s highs from 1999 through 2008. On the warmer side, seven highs (22%) were in the: 50s (4), 60s (2) and 70s (1). On the cold side, seven highs (22%) were in the: 20s (1) and 30s (6). The most recent 30s high was 37 in 1997. There were only two 70s highs in the history of O'Hare on this date. They are 74 in 1969 and 70 in 1979.

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 a warm 69 with a low of 34, a 35 degree spread and warm day. In 1975 the high was 59 with a low of 43, a warm day. In 1971 the high was 39 with a low of 34, a five degree spread. In 1969 the high was a warm 74 with a low of 38, a 36 degree spread, year of the record high and warm day. That high of 74 is also the record high, although it was set at Midway. In 1968 the high was a warm 65 with a low of 40, a warm day. In 1967 the high was 33 with a low of 11, a cold day. In 1966 the high was 61 with a low of 43, a warm day. In 1965 the high was 24 with a low of 10, a cold day. In 1964 the high was 37 with a cold low of 9, another cold day. In 1961 the high was a cold 34 degrees. In 1960 the high was 31 with a low of 17, another cold day. In 1959 the low was a cold 17 degrees.

More recently, we had small spreads of four degrees in 1984 (31/27), five degrees in 1983 (40/35), six degrees in 1987 (42/36), six degrees three years ago in 2008 (42/36), seven degrees in 1992 (36/29) and seven degrees in 2003 (44/37).

On the cold side, in 1993 the high was 31 with a low of 14. Four years before, in 1989, the high was 29 with a low of 17. In 1981 the high was 35 with a low of 15. Another cold high was 31 in 1984. The record low of 3 was set back in 1923. The record coldest high of 20 occurred way back in 1875. 25 of the last 31 lows (78%) were in the: 20s (14) and 30s (11). Four lows were in the cold 10s (a.k.a. teens). All of the 10s lows occurred between 1981 and 1993. Three lows were in the warmer 40s. The past two years produced lows in the 40s. The other one occurred in the first year of the 32-year period, 1979.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:33 and sunrise is at 7:01. Sunset is at 19:03 and twilight ends at 19:31. There's a total of 12 hours, 2 minutes of daylight today and 12 hours, 58 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 6:31 and sunrise is at 6:59. The moon is waxing gibbous and will be full tomorrow. Illumination was 96% at midnight, will be 98% at noon and 99% at midnight tonight. Moonset is at 5:59 this morning. Moonrise is at 18:10 tonight. Moonset is at 6:29 tomorrow morning. Moonlight time is 11 hours, 49 minutes which is 47 minutes shorter than yesterday. The Spring Equinox is in two days at 18:21.

April Fool's Day is 14 days. The warm part of Spring (Warm Spring) begins in 26 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-