April 20: ORD

Today is April 20th. It's the 110th day of the year. 255 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 59 and the normal low is 39. I've calculated the 32-year averages at 62 and 42.

On the warm side, in 1985 the high was the record high of 87 with the near-record warmest low of 63. The record warmest low of 64 occurred in 1957. Two years later, in 1987, the high was 86 with a low of 56, a 30 degree spread. In 2001 the high was 77 with a low of 51. Five years later, in 2006, the high was 75 with a low of 53. In 1992 the high was 71 with a low of 55. In 1979 the high was 69 with a low of 54. A year later, in 1980, the high was 76 with a low of 47. Another warm high was 72 three years ago in 2008. Another warm low was 51 in 1990. 19 of the last 32 highs (59%) were in the: 50s (9) and 60s (10). On the warmer side, eight highs (25%) were in the: 70s (6) and 80s (2). On the cold side, five highs (16%) were in the 40s.

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 cold 41 with a low of 34, a seven degree spread and cold day. In 1977 the high was 78 with a near-record warmest low of 63, a warm day. In 1976 the low was a warm 51 degrees. In 1975 the high was a cold 47 degrees. In 1974 the high was a warm 79 with a low of 46, a 33 degree spread and warm day. In 1973 the high was 77 with a low of 62, a warm day. In 1971 the high was a warm 76 with a low of 47, another warm day. In 1969 the high was 66 with a low of 33, a 33 degree spread. In 1968 the high was a warm 75 with a low of 50, a warm day. In 1960 the high was a warm 74 with a low of 49, another warm day. In 1959 the high was a cold 42 with a low of 32, a cold day.

More recently, we had small spreads of six degrees in 1991 (44/38), six degrees in 1995 (47/41) and seven degrees in 2002 (48/41). We had large spreads of 31 degrees in 1989 (69/38) and 30 degrees in 2007 (68/38).

On the cold side, in 1981 the high was 41 with a low of 30. In 1993 the high was 41 with a low of 35. Another cold low was 27 in 1983. Other cold highs were 44 in 1991 and 47 in 1995. The record low of 24 was set way back in 1897. The record coldest high of 32 occurred way back in 1904. 23 of the last 32 lows (72%) were in the: 30s (14) and 40s (9). One low (3%) was in the cold 20s. Eight lows (25%) were in the warmer: 50s (7) and 60s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:36 and sunrise is at 6:05. Sunset is at 19:40 and twilight ends at 20:10. There's a total of 13 hours, 35 minutes of daylight today and 14 hours, 34 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 5:34 and sunrise is at 6:04. The moon is was full three nights ago as the full Pink (a.k.a. Sprouting Grass, Egg or Fish) moon at 21:44. "Pink" moon refers to the wild ground phlox. The moon is now waning gibbous. Illumination was 93% at midnight, will be 90% at noon and 87% at midnight tonight. Moonset is at 7:34 this morning. Moonrise is at 23:16 tonight. Moonset is at 8:30 tomorrow morning. Moonlight time is 8 hours, 18 minutes which is 19 minutes shorter than yesterday. Moonlight time is at it's shortest today.

The warm part of Spring (Warm Spring) began a week ago. 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. Good Friday and Earth Day are in two days. -Bernie-