Sunday, October 31, 2010

October 31: ORD

Today is October 31st. It's the 304th day of the year. 61 days remain. It's week 44 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 55 and the normal low is 37. I've calculated the 31-year averages at 59 and 42.


On the warm side, in 1979 the high was 75 with a low of 53. Two years later, in 1981, the high was 72 with a low of 54. In 1997 the high was 65 with a low of 54. In 2001 the high was 68 with a low of 50. Two years ago the high was 70 with a low of 48. In 2000 the high was 70 with a low of 47. In 2003 the high was 67 with a low of 49. In 1982 the high was 64 with a low of 51. In 1990 the high was 73 with a low of 42, a 31 degree spread. In 1999 the high was 69 with a low of 46. Other warm lows were 54 in 1998 and 50 in 2005. The record high of 84 was set in 1950. The record warmest low of 65 occurred in 1974.
22 of the last 31 highs (71%) have been: 50s (12) and 60s (10). Five highs were in the warmer 70s and four highs were in the cooler 40s. 2008 and 2009 rank as one of the warmest and coolest as highs were 70 and 46 respectively.

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1974 the high was 77 with a low of 65, a warm day and year of the record warmest low. In 1973 the high was 49 with a low of 42, a seven degree spread. In 1972 the high was 46 with a low of 44, a two degree spread. In 1969 the high was 50 with a low of 47, a three degree spread. In 1968 the high was a warm 79 with a low of 42, a 37 degree spread and overall warm day. In 1967 the high was 51 with a warm low of 49, a two degree spread. In 1964 the high was a warm 67 degrees with a low of 29, a 38 degree spread. In 1959 the high was 50 with a low of 46, a four degree spread.


More recently, there were
no other large spreads. There were small spreads of five degrees in 1998 (59/54) and seven degrees in 2005 (57/50).

On the cool side, in 1996 the high was 40 with a low of 26. In 1993 the high was 44 with a low of 25. The record low of 23 and record coolest high of 31 occurred on the same cold, winter-like day way back in 1873. 21 of the last 31 lows (68%) were: 30s (9) and 40s (12). Three lows were in the cooler 20s and seven lows were in the warmer 50s. The 20s lows occurred in a nine year period between 1988 and 1996. The most recent 50s low was 50 in 2005. For 14 years (from 1983 through 1996) lows were below 50.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:56 and sunrise is at 7:25. Sunset is at 17:48 and twilight ends at 18:17. There's a total of 10 hours, 23 minutes of daylight today and 11 hours, 21 minutes between twilights. We are losing two or three minutes of daylight a day. Tomorrow twilight begins at 6:57 and sunrise is at 7:26. The moon reached last quarter yesterday at 7:46 in the morning and is waning crescent. Illumination was 42% at midnight, will be 36% at noon and 31% at midnight tonight. Moonrise was at 0:43 this morning. Moonset is at 14:31 this afternoon. Moonrise is at 1:57 tomorrow morning. Moonlight time is 13 hours, 48 minutes which is 12 minutes shorter than yesterday.

Halloween is today. Election Day is in two days. Veteran's Day is in 11 days. -Bernie-

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