April 21: ORD

Today is April 21st. It's the 111th day of the year. 254 days remain. It's week 16 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 60 and the normal low is 39. I've calculated the 31-year averages at 60 and 40.

On the warm side, in 1985 the high was the record high of 88 with the record warmest low of 63. In 2001 the high was 82 with a low of 55. In 1980 the high was 79 with a low of 46, a 33 degree spread. Other warm highs were 77 three years ago, 75 two years ago and 72 in 1987. 13 of the last 31 highs were 50s. On the warmer side, 14 highs were: 60s (7), 70s (5) and 80s (2). On the colder side, four highs were 40s.

In looking back through the years to the first April at O'Hare in 1959, the following instances were notable: In 1976 the low was a warm 52. In 1974 the high was 70 with a low of 61, a warm day. In 1973 the high was 68 with a warm low of 59, a warm day. In 1972 the high was a cold 47 with a low of 41, a six degree spread. In 1968 the low was a warm 53. In 1967 the high was 72 with a low of 51, a warm day. In 1964 the high was a warm 72. In 1962 the high was a warm 80 with a low of 44, a warm day. In 1960 the high was 73 with a low of 55, another warm day. In 1959 the high was a cold 47 with a low of 29, a cold day.

More recently, we had small spreads of three degrees in 2002 (42/39), six degrees in 1998 (53/47) and seven degrees last year (44/37). The large spreads were: 34 degrees two years ago (77/43), 33 degrees last year (75/42) and 32 degrees in 1987 (72/40).

On the cold side, in 1986 the high was 45 with the record low of 27. Two years later, in 1988, the high was 45 with a low of 29. Another cold high was 42 in 2002 and 44 last year. The record coldest high of 35 was set back in 1936. 17 of the last 31 lows were 40s. 12 lows were in the colder: 20s (4) and 30s (8). Two lows were in the warmer: 50s (1) and 60s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:34 and sunrise was at 6:03. Sunset is at 19:42 and twilight ends at 20:11. There's a total of 13 hours, 39 minutes of daylight today and 14 hours, 37 minutes between twilights. Tomorrow twilight begins at 5:32 and sunrise is at 6:02. The moon reached first quarter today at 13:20. Illumination was 44% at midnight, will be 50% at noon and 56% at midnight tonight. Moonset was at 2:01 this morning. Moonrise was at 11:55. Moonset is at 2:36 early tomorrow morning. Moonlight time is 14 hours, 6 minutes which is 30 minutes shorter than yesterday.

Earth Day is tomorrow and Arbor Day is in three days. - Bernie -