May 12: ORD

Today is May 12th. It's the 132nd day of the year. 233 days remain. It's week 19 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 68 and the normal low is 46. I've calculated the 31-year averages at 67 and 46.

On the warm side, in 2004 the high was 85 degrees with the record warmest low of 66. In 1991 the high was 84 with a low of 63. In 2000 the high was 85 with a low of 60. In 1992 the high was 77 with a low of 62. Other 80s highs were 84 in 1993, 81 in 1982, 80 in 1988 and 80 in 1985. The only upper 70s high was 79 in 1998. The record high of 92 occurred in 1956. 30 of the last 31 highs (97%) were in the: 50s (8), 60s (8), 70s (7) and 80s (7). On the cooler side, one high was in the 40s.

In looking back through the years to the first May at O'Hare in 1959, the following instances were notable: In 1974 the high was a cool 55 with a low of 48, a seven degree spread. In 1973 the high was a cool 56. In 1970 the high was a warm 81 with a low of 49, a 32 degree spread. In 1968 the high was 77 with a low of 46, a 31 degree spread. In 1967 the high was 52 with a low of 38, a cool day. In 1966 the high was a cold 44 with a low of 40, a four degree spread and cold day. In 1965 the high was a warm 81 with a low of 47, a 34 degree spread. In 1961 the high was a warm 83 with a low of 50, a 33 degree spread. In 1960 the low was a cold 34.

More recently, we had large spreads of 43 degrees in 1993 (84/41), 32 degrees in 1998 (79/47), 32 degrees in 2009 (71/39), 31 degrees in 1981 (62/31) and 30 degrees in 1982 (81/51).

On the cool side, in 2006 the high was 47 with a low of 36. A decade earlier, in 1996, the high was 50 with a low of 35. The other 30s lows were the record low of 31 in 1981, 38 in 1989, 38 in 2001 and 39 last year. The other cool highs (lower and mid 50s) were: 50 in 2002, 54 in 1979, 55 in 1990, 55 in 2005 and 56 two years ago. The record coldest high of 44 was set way back in 1882. 16 of the last 31 lows were 40s. Six lows were in the colder 30s. Nine lows were in the warmer: 50s (5) and 60s (4).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight began at 5:04 and sunrise was at 5:35. Sunset is at 20:05 and twilight ends at 20:36. There's a total of 14 hours, 30 minutes of daylight today and 15 hours, 32 minutes between twilights. Tomorrow twilight begins at 5:02 and sunrise is at 5:34. The moon is waning crescent and reaches new tomorrow at 20:04. Illumination was 4% at midnight, will be 2% at noon and 1% at midnight tonight. Moonrise was at 4:21 this morning. Moonset is at 19:04. Moonrise is at 4:55 tomorrow morning. Moonlight time is 14 hours, 43 minutes which is 39 minutes longer than yesterday. Too bad there's so little of it to see!

Armed Forces Day is in three days. - Bernie -