March 24: ORD

Today is March 24th. It's the 83rd day of the year. 282 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 49 and the normal low is 31. I've calculated the 31-year averages at 52 and 32.

On the warm side, last year the high was 69 with a low of 48. In 2003 the high was 74 with a low of 42, a 32 degree spread. Four years later, in 2007, the high was 64 with a low of 52. In 1987 the high was 69 with a low of 45. In 2000 the high was 68 with a low of 46. In 1988 the high was 71 with a low of 42. In 2004 the high was 63 with a low of 44. Other warm highs were 64 in 1989, 63 in 1996 and 62 in 1994. The record high of 79 was set back in 1939 and the record warmest low of 61 was set back in 1910. 25 of the last 31 highs were: 40s (8), 50s (9) and 60s (8). On the warmer side, two highs were in the 70s. On the colder side, four highs were in the 30s. Today is the mean (average) date for 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 1978 the high was a cold 33 with a low of 24, a cold day. In 1976 the high was 70 with a low of 49, a warm day. In 1975 the high was 58 with a low of 28, a 30 degree spread. In 1974 the high was 15 with a low of 5, a very cold day and the year that the records were established (at Midway, see "cold side" below). In 1972 the high was a cold 35 with a low of 28, a seven degree spread. In 1971 the high was 37 with a low of 18, a cold day. In 1966 the high was 27 with a low of 18, a cold day. In 1965 the high was 23 with a low of 5, another cold day. In 1963 the high was 74 with a low of 47, a warm day. In 1960 the high was 27 with a low of 13, a cold day. In 1959 the high was a warm 74 with a low of 38, a 36 degree spread and warm day.

More recently, we had a small spread of seven degrees in 1985 (42/35). There were large spreads of 32 degrees in 1989 (64/32) and 33 degrees in 1992 (58/25).

On the cold side, in 1983 the high was 31 with a low of 18. In 2001 the high was 36 with a low of 21. The record low of 5 and record coldest high of 17 were set on the same day in 1974. 23 of the last 31 lows were: 20s (14) and 30s (9). One low was in the colder 10s (a.k.a. teens). Seven lows were in the warmer: 40s (6) and 50s (1).

Today is a major day in Chicago's snow history. At O'Hare in 1965, this was the fifth of seven days in which a total of 10.2 inches fell. Today 0.5 inches fell. In 1970, this was the first of five days in which 11.8 inches fell. Today 0.1 inches fell. In 1930 at the University of Chicago, a total of 21.6 inches fell on the 24th and 25th. 14.4 inches fell in an unspecified 24 hour timeframe during these two days. Tom Skilling of WGN-TV said in his blog that the total was 19.2 inches. So there appears to be a slight discrepancy between the totals.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 6:22 and sunrise was at 6:50. Sunset is at 19:10 and twilight ends at 19:38. Chicago's sunset and end of twilight times are each three minutes earlier. There's a total of 12 hours, 20 minutes of daylight today and 13 hours, 16 minutes between twilights. Tomorrow twilight begins at 6:20 and sunrise is at 6:48. The moon reached first quarter yesterday at 6:00. Illumination was 59% at midnight, will be 65% at noon and 70% at midnight tonight. Moonset was at 3:21 this morning. Moonrise is at 12:51. Moonset is at 4:02 tomorrow morning. Moonlight time is 14 hours, 30 minutes which is 24 minutes shorter than yesterday.

Palm Sunday is in four days. April Fool's Day is in eight days. -Bernie-