April 3: ORD

Today is April 3rd. It's the 93rd day of the year. 272 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 53 and the normal low is 34. I've calculated the 32-year averages at 56 and 37.

On the warm side, in 1981 the high was 75 with a low of 59. In 1999 the high was 73 with a low of 52. Two years earlier, in 1997, the high was 67 with a low of 52. Other warm highs were 70 in 1996, 70 in 2007 and 65 in 1991. Another warm low was 49 last year, in 2010. The record high of 81 was set in 1956 and the record warmest low of 60 occurred back in 1928. 28 of the last 32 highs (88%) were in the: 40s (9), 50s (10) and 60s (9). Our most recent 40s high was 47 in 2003. Our most recent 60s high was 64 in 2005. On the warmer side, four highs were in the 70s.

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 70 with a low of 37, a 33 degree spread. In 1976 the high was a warm 72 with a low of 45, a warm day. In 1975 the high was 31 with a low of 19, a cold day. In 1974 the high was 65 with a low of 50, a warm day. In 1973 the high was 44 with a low of 38, a six degree spread. In 1971 the high was a cold 40 degrees. In 1968 the high was 62 with a warm low of 48, a warm day. In 1966 the high was a cold 40 degrees. In 1964 the high was a cold 38 degrees. In 1963 the high was a warm 70 with a low of 39, a 31 degree spread and warm day. In 1960 the high was 42 with a low of 37, a five degree spread.

More recently, we had a small spread of three degrees in 1983 (40/37). There were large spreads of 32 degrees in 2004 (59/27), 33 degrees in 2005 (64/31), 35 degrees in 2007 (70/35), 37 degrees in 1982 (62/25) and 38 degrees in 1996 (70/32).

On the cold side, in 1987 the high was 40 with the record low of 17. The record low of 17 also occurred way back in 1879. In 1993 the high was 44 with a low of 22. Other cold highs were 40 in both 1983 and 2002. The record coldest high of 30 was set in 1954. 16 of the last 31 lows (50%) were in the 30s. Six lows (19%) were in the cold: 10s (a.k.a. teens) (1) and 20s (5). Ten lows (31%) were in the warmer: 40s (7) and 50s (3).

Today is a major day in Chicago's snow history. At O'Hare and Midway in 1975, this was the second day of a two day storm. At O'Hare, 0.4 inches of an 11.1 inch total occurred. At Midway, 0.4 inches of a 9.8 inch total occurred.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:05 and sunrise is at 6:33. Sunset is at 19:21 and twilight ends at 19:50. There's a total of 12 hours, 48 minutes of daylight today and 13 hours, 45 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:03 and sunrise is at 6:31. The moon is waning crescent and reaches new today at 9:32. Illumination was 0% at midnight, will be 0% at noon and 1% at midnight tonight. Moonrise is at 6:10 this morning. Moonset is at 19:49 this afternoon. Moonrise is at 6:36 tomorrow morning. Moonlight time is 13 hours, 39 minutes which is 37 minutes longer than yesterday.

The warm part of Spring (Warm Spring) begins in 10 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-