October 14: ORD

Today is October 14th. It's the 288th day of the year. 78 days remain. It's week 41 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.Before this, the official site of record was on the south side of Chicago at Midway International Airport (MDW), beginning on Wednesday, July 1, 1942. From Friday, January 1, 1926 through Tuesday, June 30, 1942, the official site was at the University of Chicago. Before this, the official site was at various locations in Chicago going back to Monday, October 16, 1871. Observations taken from October 15, 1870 to October 8, 1871 were lost in the Great Chicago Fire.

According to the National Climatic Data Center (NCDC), the normal high is 63 and the normal low is 43. I've calculated the 33-year averages at 62 and 44.

On the warm side, in 1989 the high was 85 (O'Hare's co-second hottest high of the date with 1975) with a low of 52, a 33 degree spread. In 2000 the high was 74 with a low of 60. In 1984 the high was 70 with a low of 62. The record high of 89 degrees was set in 1975 at Midway. The record warmest low of 66 degrees occurred way back in 1879, a time when the official readings were taken adjacent to Lake Michigan. 17 of the past 33 highs (52%) were in the 60s. Five highs (15%) were in the warm: 70s (4) and 80s (1). 11 highs (33%) were in the cool: 40s (3) and 50s (8). Two years share the distinction of being O'Hare's warmest October 14ths. They are: 1962 with a high of 86 (O'Hare's hottest high of the date) with a low of 61 AND 1975 with a high of 85 (O'Hare's co-second hottest high of the date with 1989) with a low of 62. O'Hare's second warmest October 14th was in 1968 as the high was 81 with a low of 64 (O'Hare's warmest low of the date). The other warm day was in 1966 as the high was 70 with a low of 63 (O'Hare's second warmest low of the date). The other warm highs were 77 degrees in 1963, 76 degrees in 2005 and 75 degrees in 1973. The other warm low of 58 degrees occurred in 1960. 

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1978 the high was a cool 51 degrees. In 1976 the high was 70 with a low of 37, a 33 degree spread. In 1975 the high was 85 with a low of 62, a hot day. 1975 was the year of the record high of 89 at Midway. In 1973 the high was a warm 75 degrees. In 1969 the high was a cool 51 degrees. In 1968 the high was 81 with a low of 64, a warm day. In 1966 the high was 70 with a warm low of 63, a seven degree spread and warm day. In 1965 the high was 71 with a low of 39, a 32 degree spread. In 1964 the high was 70 with a low of 33, a 37 degree spread. 1963 was a dual day. The high of 77 was way warmer than normal and the low of 29 was way colder than normal. The spread of 48 degrees was incredible, rarely seen. In 1962 the high was 86 with a low of 61, a hot day. In 1960 the low was a warm 58 degrees. In 1959 the high was a cool 50 degrees.

More recently, there was an additional large spread of 31 degrees in 1979 (62/31). The small spread was six degrees three years ago, in 2009 (48/42).

On the cool side, in 2006 the high was 50 with a low of 32. Two decades earlier, in 1986, the high was 48 (one of O'Hare's co-coolest highs of the date) with a low of 34. 2006 and 1986 are O'Hare's co-coolest October 14ths. The record low of 27 degrees was set way back in 1872 at a time when the official readings were taken adjacent to Lake Michigan. The record coolest high of 43 degrees occurred back in 1937 at the University of Chicago. 26 of the last 33 lows (79%) were in the: 30s (11) and 40s (15). O'Hare recorded two sets of six consecutive lows in the 30s and 40s (from 1990 through 1995 and from 2001 through 2006). Seven lows (21%) were in the warm: 50s (5) and 60s (2). O'Hare's other cold lows are 29 degrees in 1963 (O'Hare's coldest low of the date), 30 degrees in 2002 and 31 degrees in 1979. O'Hare's other cool highs are 48 degrees in 2009 (one of O'Hare's co-coolest highs of the date), 49 degrees in 1997, 50 degrees in 1959, 51 degrees in 1969 and 51 degrees in 1978. 

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:37 and sunrise is at 7:05. Sunset is at 18:12 and twilight ends at 18:40. There's a total of 11 hours, 7 minutes of daylight today and 12 hours, 3 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:38 and sunrise is at 7:07. The moon is waning crescent, heading towards new tomorrow at 7:02. Illumination was 2% at midnight, will be 1% at noon and 0% at midnight tonight. Moonrise was at 6:05 this morning. Moonset is at 17:31 this afternoon. Moonrise is at 7:19 tomorrow morning. Moonlight time is 11 hours, 26 minutes which is 39 minutes shorter than yesterday.

Warm Fall began September 22nd and runs for 41 days through November 1st. High temperatures in this period are usually in the 50s, 60s and 70s. Highs in the 30s and 40s occur infrequently. United Nations Day is in ten days. Standard Time doesn't return until November 4th.