April 13: ORD

Today is April 13th. It's the 103rd day of the year. 262 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 37. I've calculated the 32-year averages at 57 and 38.

On the warm side, in 2006 the high was 80 with a low of 52. Twenty-five years before that, in 1981, the high was 79 with a low of 50. Four years later, in 1985, the high was 71 with a low of 54. In 1998 the high was 68 with a low of 55. Fifteen years prior, in 1983, the high was 70 with a low of 47. Another warm high was 73 in 1988 (our most recent 70s high). 1988 also had the largest spread (see below). The record high of 82 and record warmest low of 62 were set on the same warm day in 1941. The record high of 82 was first set way back in 1887. 27 of the last 32 highs (84%) were in the: 40s (8), 50s (12) and 60s (7). On the warmer side, five highs were in the: 70s (4) and 80s (1). Our most recent 70s high was Note that all highs have made it out of 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 a warm 77 with a low of 47, a 30 degree spread and warm day. In 1976 the high was a warm 69 with a low of 32, a 37 degree spread. In 1974 the high was a warm 71 with a low of 48, a warm day. In 1972 the high was a warm 70 with a low of 39, a 31 degree spread. In 1968 the high was 71 with a low of 58, a warm day. In 1967 the high was a warm 72 with a low of 45, another warm day. In 1964 the low was a warm 51 degrees. In 1962 the high was a cold 43 degrees. In 1960 the high was 76 with a low of 53, a warm day.

More recently, we had large spreads of 38 degrees in 2003 (67/29) and 41 degrees in 1988 (73/32).

On the cold side, in 1980 the high was 46 with a low of 24. Three years ago, in 2008, the high was 42 with a low of 32. Another cold high was 43 in 1992. The record low of 21 and record coldest high of 33 were set on the same cold day in 1950. 17 of the last 32 lows (53%) were in the 30s. Four lows (13%) were in the cold 20s. 11 lows (34%) were in the warmer: 40s (7) and 50s (4).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:47 and sunrise is at 6:16. Sunset is at 19:32 and twilight ends at 20:01. There's a total of 13 hours, 16 minutes of daylight today and 14 hours, 14 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 5:46 and sunrise is at 6:15. The moon is waxing gibbous, having reached first quarter two days ago at 7:05. Illumination was 69% at midnight, will be 74% at noon and 79% at midnight tonight. Moonset is at 3:24 this morning. Moonrise is at 14:29 this afternoon. Moonset is at 3:55 tomorrow morning. Moonlight time is 12 hours, 55 minutes which is 40 minutes shorter than yesterday.

The warm part of Spring (Warm Spring) begins today. 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 four days. -Bernie-