October 16: ORD

Today is October 16th. It's the 289th day of the year. 76 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.

According to the National Climatic Data Center (NCDC), the normal high is 62 and the normal low is 43. I've calculated the 32-year averages at 62 and 43.

On the warm side, in 1998 the high was 80 (the only 80s high of the past 32 years and fourth in O'Hare's history on October 16th) with a low of 55. Four years earlier, in 1994, the high was 76 with a low of 57. The other warm highs were 75 in 1988 and 74 in 1980. The other warm low was 57 in 1996. The record high of 87 was set in 1963 and the record warmest low of 68 occurred way back in 1897. The National Weather Service has this low of 68 occurring in 1879. 29 of the past 32 highs (91%) were in the: 50s (11), 60s (10) and 70s (8). Our most recent 70s high occurred last year (71 in 2010). Before that, it happened 16 years earlier in 1994 (76 degrees). One high was in the warm 80s (80 in 1998). Two highs were in the cold 40s (both occurred recently: 45 two years ago in 2009 and 47 in 2004).

In looking back through the years to the first October at O'Hare in 1959, the following instances were notable: in 1970 the low was a cold 30 degrees. In 1968 the high was 82 with a low of 65, a warm day. In 1965 the high was 80 with a low of 56, a warm day. In 1964 the high was a warm 76 with a low of 37, a 39 degree spread. In 1963 the high was 85 with a low of 56, a warm day and year of the record high of 87 at Midway. In 1962 the high was 73 with a low of 42, a 31 degree spread. In 1961 the high was 70 with a low of 40, a 30 degree spread.

More recently, there were large spreads of 34 degrees in 1991 (62/28), 31 degrees in 1983 (72/41) and 31 degrees last year, in 2010 (71/40). The lone small spread was six degrees two years ago, in 2009 (45/39).

On the cool side, in 1992 the high was 50 with a low of 29. The other cool highs were 45 two years ago in 2009 and 47 in 2004. The record low of 28 was set in 1991. The record coolest high of 44 occurred back in 1943. 30 of the last 32 lows (94%) were in the: 30s (11), 40s (11) and 50s (8). Two lows were in the cold 20s. The two cold 20s lows were in the back-to-back years of 1991 and 1992. These are the only 20s lows in the history of O'Hare on October 16th.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:39 and sunrise is at 7:07. Sunset is at 18:10 and twilight ends at 18:39. There's a total of 11 hours, 3 minutes of daylight today and 12 hours between twilights. We lost three minutes of daylight from yesterday. Tomorrow twilight begins at 6:40 and sunrise is at 7:08. The moon is waning gibbous. Illumination was 85% at midnight, will be 82% at noon and 78% at midnight tonight. Moonset is at 11:29 this morning. Moonrise is at 20:51 tonight. Moonset is at 12:19 tomorrow afternoon. Moonlight time is 14 hours, 38 minutes which is 8 minutes longer than yesterday.

Warm Fall began September 22 and runs for 41 days through November 1. 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 eight days.