April 12: ORD

Today is April 12th. It's the 102nd day of the year. 263 days remain. It's week 15 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 57 and the normal low is 36. I've calculated the 32-year averages at 55 and 38.

On the warm side, in 2006 the high was 76 with a low of 58. In 1998 the high was 73 with a low of 55. In 1979 the high was 77 with a low of 45, a 32 degree spread. In 1985 the high was 76 with a low of 43, a 33 degree spread. Another warm high was 70 last year (in 2010). The record high of 86 was originally set in 1971 and tied in 1977. The record warmest low of 60 occurred in 1896. The low at Midway in 1977 was 58 degrees. 21 of the last 32 highs (66%) were in the: 40s (9) and 50s (12). On the warmer side, nine highs (28%) were in the: 60s (4) and 70s (5). On the cold side, two highs 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 1977 the high was 83 with a low of 57, a warm day and year of the record high (86 at Midway). In 1974 the high was 73 with a low of 53, a warm day. In 1971 the high was a warm 85 with a low of 45, a 40 degree spread and warm day. 1971 is also the year of the record high (86 at Midway). In 1968 the high was 81 with a low of 54, a warm day. In 1964 the low was a warm 51 degrees. In 1963 the high was 61 with a low of 26, a 35 degree spread. In 1962 the high was a cold 45 degrees. In 1961 the high was a cold 44 with a low of 37, a seven degree spread. In 1960 the high was a warm 72 with a low of 42, a 30 degree spread.

More recently, we had small spreads of five degrees in 2007 (38/33) and seven degrees in 1981 (50/43).

On the cold side, in 1997 the high was 36 with a low of 30, a six degree spread. In 1990 the high was 45 with a low of 25. Other cold highs were 38 in 2007, 41 in 1992, 42 in 2004, 42 three years ago in 2008 and 44 in 1995. The record low of 21 was set back in 1939 and tied in 1957. The record coldest high of 34 occurred in 1950. 26 of the last 32 lows (81%) were in the: 30s (16) and 40s (10). Four lows were in the cold 20s. Two lows were in the warmer 50s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:49 and sunrise is at 6:18. Sunset is at 19:31 and twilight ends at 20:00. There's a total of 13 hours, 13 minutes of daylight today and 14 hours, 11 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 5:47 and sunrise is at 6:16. The moon is waxing gibbous, having reached first quarter yesterday at 7:05. Illumination was 58% at midnight, will be 64% at noon and 69% at midnight tonight. Moonset is at 2:51 this morning. Moonrise is at 13:16 this afternoon. Moonset is at 3:24 tomorrow morning. Moonlight time is 13 hours, 35 minutes which is 33 minutes shorter than yesterday.

The warm part of Spring (Warm Spring) begins tomorrow 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 five days. -Bernie-