April 23: ORD

Today is April 23rd. It's the 113th day of the year. 252 days remain. It's week 17 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 61 and the normal low is 40. I've calculated the 31-year averages at 62 and 40.

On the warm side, in 1985 the high was 77 with a low of 59. Five years later, in 1990, the high was 80 with a low of 49, a 31 degree spread. Two years ago the high was 74 with a low of 53. Another warm high was 75 in 1979. The record high of 88 and record warmest low of 66 were set on the same day in 1960 at Midway. 26 of the last 31 highs were: 50s (7), 60s (11) and 70s (8). On the warmer side, one high was in the 80s. 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 1975 the high was a warm 74. In 1974 the high was a cold 44 with a low of 37, a seven degree spread. In 1971 the high was 68 with a low of 32, a 36 degree spread. In 1969 the high was a cold 49. In 1967 the high was 43 with a low of 26, a cold day. In 1963 the high was a cold 45. In 1960 the high was 86 with a low of 66, a warm day. 1960 was the year of the record high and record warmest low, both at Midway.

More recently, we had a small spread of seven degrees in 1988 (47/40). The large spreads were 38 degrees in 1986 (63/25), 34 degrees in 1994 (69/35), 33 degrees in 1979 (75/42), 32 degrees in 1998 (72/40), 31 degrees in 1980 (72/41), 31 degrees in 2006 (72/41), 30 degrees in 1982 (67/37) and 30 degrees last year (67/37).

On the cold side, in 2005 the high was 42 with a low of 35, a seven degree spread. In 1984 the high was 41 with a low of 37, a four degree spread. The other cold low was the record low of 25 in 1986. Other cold highs were 47 in 1988 and 48 in 1999. The record coldest high of 35 was set back in 1910. 27 of the last 31 lows were: 30s (15) and 40s (12). One low was in the colder 20s and three lows were in the warmer 50s.

Today is a major day in Chicago's snow history. In 1967, 3.4 inches fell at O'Hare. Midway had 3.1 inches and Rockford had 3.8 inches.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:30 and sunrise was at 6:00. Sunset is at 19:44 and twilight ends at 20:14. There's a total of 13 hours, 44 minutes of daylight today and 14 hours, 44 minutes between twilights. Tomorrow twilight begins at 5:29 and sunrise is at 5:59. The moon reached first quarter two days ago at 13:20 and is waxing gibbous. Illumination was 67% at midnight, will be 72% at noon and 77% at midnight tonight. Moonset was at 3:07 this morning. Moonrise is at 14:24. Moonset is at 3:35 tomorrow morning. Moonlight time is 12 hours, 43 minutes which is 44 minutes shorter than yesterday.

Arbor Day is tomorrow. - Bernie -