October 19: ORD

Today is October 19th. It's the 293rd day of the year. 73 days remain. It's week 42 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 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 61 and the normal low is 42. I've calculated the 33-year averages at 59 and 41.

On the warm side, in 1979 (O'Hare's second warmest October 19th) the high was 74 with the record warmest low of 65. In 1994 the high was 74 with a low of 55. A year later, in 1995, the high was 79 (O'Hare's second hottest high of the date) with a low of 49, a 30 degree spread. The other warm highs were 77 degrees in 1962, 76 degrees in 2000 and 75 degrees in 1973. The record high of 84 degrees was set in 1971 at Midway. 24 of the past 33 highs (73%) were in the: 50s (10) and 60s (14). Our most recent 50s high was 52 degrees in 2004. 9 of the past 15 highs (60%) were in the 60s, including four in a row from 2007 through 2010. Four highs (12%) were in the warm 70s. Five highs (15%) were in the cold 40s. O'Hare's warmest October 19th was in 1971 as the high was 83 (O'Hare's hottest and only 80s high of the date) with a low of 64 (O'Hare's second warmest low of the date). The other warm day was in 1965 as the high was 77 with a low of 50. 

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1976 the high was a cold 46 degrees. In 1975 the high was 54 with a low of 47, a seven degree spread. In 1973 the high was a warm 75 with a low of 41, a 34 degree spread. In 1972 the high was 42 with a low of 26, a cold day. In 1971 the high was 83 with a low of 64, a warm day. 1971 was the year of the record high of 84. In 1965 the high was a warm 77 with a low of 50, a warm day. In 1964 the high was 47 with a low of 27, a cold day. In 1962 the high was a warm 77 with a low of 44, a 33 degree spread.

More recently, there was an additional large spread of 33 degrees in 1997 (66/33). There were additional small spreads of three degrees in 2004 (52/49), five degrees in 2006 (44/39) and five degrees last year in 2011 (49/44).

On the cool side, in 1992 (O'Hare's coolest October 19th) the high was 46 with the record low of 21. Three years earlier, in 1989, the high was 40 (O'Hare's coolest high of the date) with a low of 33, a seven degree spread. Two years later, in 1991, the high was 47 with a low of 29. A year earlier, in 1990, the high was 52 with a low of 28. In 1981 the high was 53 with a low of 28. The other cold low was 30 degrees in 1996. The other cool highs were 44 degrees in 2006 and 46 degrees in 1976. The record coolest high of 36 degrees occurred back in 1930 at the University of Chicago. 24 of the last 33 lows (73%) were in the: 30s (9) and 40s (15). Four lows (12%) were in the cold 20s, three of which occurred in 1990, 1991 and 1992. Five lows (15%) were in the warm: 50s (4) and 60s (1). O'Hare's second coolest October 19th was in 1972 as the high was 42 (O'Hare's second coolest high of the date) and low of 26 (O'Hare's second coldest low of the date). The other cool October 19th was in 1964 as the high was 47 with a low of 27.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:43 and sunrise is at 7:11. Sunset is at 18:04 and twilight ends at 18:33. There's a total of 10 hours, 53 minutes of daylight today and 11 hours, 50 minutes between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:44 and sunrise is at 7:12. The moon is waxing crescent. Illumination was 19% at midnight, will be 24% at noon and 29% at midnight tonight. Moonrise is at 11:59 this morning. Moonset is at 21:40 tonight. Moonrise is at 12:52 tomorrow afternoon. Moonlight time is 9 hours, 41 minutes which is one minute longer than yesterday. Moonlight time is at its least today and was 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 five days. Halloween is in 12 days. Election Day is in 18 days. Standard Time doesn't return until November 4th.