April 7: ORD

Today is April 7th. It's the 97th day of the year. 268 days remain. It's week 14 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 55 and the normal low is 35. I've calculated the 32-year averages at 55 and 34.

On the warm side, in 1991 the high was 79 with a low of 60. A decade later, in 2001, the high was the near-record high of 83 with a low of 44, a 39 degree spread. In 1980 the high was 71 with a low of 47. In 1986 the high was 79 with a low of 39, a 40 degree spread. In 1981 the high was 74 with a low of 43, a 31 degree spread. Another warm high was 77 in 1999. The record high of 84 was set way back in 1893. The record warmest low of 62 occurred back in 1929. 17 of the last 32 highs (53%) were in the: 40s (9) and 50s (8). On the warmer side, 11 highs (34%) were in the: 60s (5), 70s (5) and 80s (1). On the cold side, four highs (13%) were in the 30s.

In looking back through the years to the first April at O'Hare in 1959, the following instances were notable: In 1978 the high was a warm 73 with a low of 45, a warm day. In 1975 the high was a cold 41 degrees. In 1972 the high was 33 with a low of 21, a cold day. In 1971 the high was a warm 68 with a low of 30, a 38 degree spread. In 1970 the high was 61 with a low of 30, a 31 degree spread. In 1969 the high was a warm 71 with a low of 38, a 33 degree spread. In 1968 the high was a warm 72 with a low of 40, a 32 degree spread. In 1959 the high was 70 with a low of 51, a warm day.

More recently, we had large spreads of 30 degrees in 1994 (51/21) and 44 degrees in 1999 (77/33).

On the cold side, in 1982 the high was 34 with the record low of 7. In 2007 the high was the record coldest high of 32 with a low of 22. In 1996 the high was 39 with a low of 23. In 2003 the high was 34 with a low of 30, a four degree spread. In 1979 the high was 40 with a low of 24. In 1990 the high was 45 with a low of 22. Another cold low was 21 in 1994. Another cold high was 43 in 1997. 23 of the last 32 lows (72%) were in the: 20s (9) and 30s (14). One low (3%) was in the cold single digits (1). Remarkably, there have been no lows in the 10s (a.k.a. teens). Eight lows (25%) were in the warmer: 40s (7) and 60s (1). There have been no lows in the 50s.

1982 had the coldest temperatures. Area lows were: Rockford: 5, Barrington: 5, Chicago Botanical Gardens: 10, Midway: 10, Marengo: 6, Wheaton: 4, Aurora: 8 and Elgin: 11. In northwest Illinois, Mt. Carroll had a low of minus 2.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:58 and sunrise is at 6:26. Sunset is at 19:26 and twilight ends at 19:54. There's a total of 13 hours of daylight today and 13 hours, 56 minutes between twilights. We gained four minutes of daylight from yesterday. Tomorrow twilight begins at 5:56 and sunrise is at 6:24. The moon is waxing crescent. Illumination was 12% at midnight, will be 15% at noon and 19% at midnight tonight. Moonrise is at 8:18 this morning. Moonset is at 23:48 tonight. Moonrise is at 9:04 tomorrow morning. Moonlight time is 15 hours, 30 minutes which is 18 minutes longer than yesterday. Moonlight time is at it's maximum today.

The warm part of Spring (Warm Spring) begins in six 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. Palm Sunday is in ten days. -Bernie-