October 22: ORD

Today is October 22nd. It's the 296th day of the year. 70 days remain. It's week 43 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 60 and the normal low is 41. I've calculated the 33-year averages at 60 and 39.

On the warm side, in 1991 the high was 76 with a low of 50. Five years prior, in 1986, the high was 75 with a low of 50. The other warm highs were 76 degrees in 1979, 73 degrees in 1992, 72 degrees in 1967 and 72 degrees in 1994 (our most recent 70s high). The record high of 87 degrees was set in 1953 at Midway. The record warmest low of 66 degrees occurred back in 1920, at a time when the official readings were taken adjacent to Lake Michigan. 25 of the past 33 highs (76%) were in the: 50s (14) and 60s (11). A long, eight year stretch of years from 1998 through 2005 had highs in the 50s and 60s. Five highs (15%) were in the warm 70s. Three highs (9%) were in the cold 40s. The 70s highs, as noted above, occurred from 1979 to 1994. The most recent three occurred in a four year period from 1991 to 1994. O'Hare's warmest October 22nd was in 1963 as the high was 84 (O'Hare's hottest high of the date) with a low of 59 (O'Hare's co-warmest low of the date). O'Hare's second warmest October 22nd was in 1971 as the high was 71 with a low of 59 (O'Hare's other co-warmest low of the date). The other warm 10/22 days were: 1975 (high of 80 (O'Hare's second hottest high of the date) and low of 46) and 1978 (high of 73 and low of 52).
 
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 warm 73 with a low of 52, a warm day. In 1976 the high was 47 with a low of 25, a cold day. In 1975 the high was a warm 80 with a low of 46, a warm day. In 1973 the high was 71 with a low of 39, a 32 degree spread. In 1971 the high was 71 with a warm low of 59, a warm day. In 1969 the high was a cold 43 with a low of 31, a cold day. In 1967 the high was a warm 72 with a low of 35, a 37 degree spread. In 1964 the low was a cold 28 degrees. In 1963 the high was 84 (O'Hare's warmest) with a low of 59, a warm day.

More recently, there were large spreads of 33 degrees in 1989 (64/31), 31 degrees in 1979 (76/45), 31 degrees in 1992 (73/42) and 31 degrees last year, in 2010 (64/33). There was a small spread of six degrees in 1983 (55/49). 

On the cool side, in 1982 (O'Hare's coolest October 22nd) the high was 49 with the record low of 22. In 1997 the high was 44 (O'Hare's second coolest high of the date) with a low of 29. The record coolest high of 41 degrees occurred back in 1913, at a time when the official readings were taken adjacent to Lake Michigan. 29 of the last 33 lows (88%) were in the: 30s (16) and 40s (13). Two lows were in the cold 20s. Two lows were in the warm 50s. O'Hare's second coolest October 22nd was in 1976 as the high was 47 with a low of 25 (O'Hare's second coldest low of the date). Another cool day was in 1969 as the high was 43 (O'Hare's coolest high of the date) and low of 31. The other cold low of 28 degrees occurred in 1964.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:46 and sunrise is at 7:15. Sunset is at 18:00 and twilight ends at 18:29. There's a total of 10 hours, 45 minutes of daylight today and 11 hours, 43 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:47 and sunrise is at 7:16. The moon is waxing gibbous, having reached first quarter yesterday at 22:32. Illumination was 51% at midnight, will be 57% at noon and 62% at midnight tonight. Moonrise is at 14:14 this afternoon. Moonset is at 1:01 tomorrow morning. Moonrise is at 14:47 tomorrow afternoon. Moonlight time is 9 hours, 46 minutes which is 32 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 two days. Halloween is in nine days. Election Day is in 15 days. Standard Time doesn't return until November 4th.