November 16: ORD

Today is November 16th. It's the 320th day of the year. 45 days remain. It's week 46 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. Before that, 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 48 and the normal low is 32. I've calculated the 33-year averages at 46 and 32.

On the warm side, in 1987 the high was 61 with a low of 50 (the only 50s low in ORD history for the date). In 2004 the high was 56 with a low of 46. The other warm highs were 64 in 1988 and 60 in 2001 (our most recent 60s high). As you can see, there were back to back 60s highs and then 13 years until the next one. The other warm low was 44 two years ago in 2009. The record high of 73 was set in 1952 at Midway. The record warmest low of 53 occurred back in 1931, a time when the official readings were taken adjacent to Lake Michigan. 15 of the past 33 highs (46%) were in the 40s. 11 highs (33%) were in the warm: 50s (8) and 60s (3). Seven highs (21%) were in the cold: 20s (1) and 30s (6). There have been no 70s highs in ORD history on November 16.

In looking back through the years to the first November at O'Hare in 1958, the following instances were notable: in 1975 the high was a warm 65 degrees. In 1971 the high was a warm 68 with a low of 40, a warm day. In 1969 the high was 51 with a cold low of 20, a 31 degree spread. In 1968 the high was 46 with a low of 42, a mere four degree spread. In 1966 the high was 62 with a low of 49, a warm day. In 1963 the high was a warm 62 with a low of 42, a warm day. In 1962 the high was 48 with a low of 43, a five degree spread. In 1959 the high was 36 with a low of 6, a 30 degree spread, cold day and year of the record low, also of 6 at Midway. This was the only 0s low ever for the date at O'Hare. In 1958 the high was 63 with a low of 48, a warm day.

More recently, there was a large spread of 32 degrees in 1988 (64/32). There were small spreads of four degrees two years ago (in 2009) (48/44), five degrees in 1993 (43/38), five degrees in 2002 (36/31), five degrees in 2003 (47/42) and six degrees in 2006 (43/37).

On the cold side, in 1997 the high was 27 (the only 20s high in ORD history for the date) with a low of 17. In 1989 the high was 34 with a low of 18. These 10s (aka teens) lows were the only 10s lows in ORD history for the date. The other cold high was 36 in 2002. The record low of 6 was set in 1959 at Midway. The record coldest high of 21 was set back in 1933, a time when the official readings were taken adjacent to Lake Michigan. 24 of the last 33 lows (73%) were in the: 20s (10) and 30s (14). There were six consecutive 20s & 30s lows from 1990 through 1995. Two lows (6%) were in the cold 10s (a.k.a. teens). Seven lows (21%) were in the warm: 40s (6) and 50s (1).

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 2004 the high was 56 with a low of 46, overall 11 degrees ABOVE normal. Then in 2005 the high was 37 with a low of 21, overall 11 degrees BELOW normal.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:15 and sunrise is at 6:45. Sunset is at 16:31 and twilight ends at 17:01. There's a total of 9 hours, 46 minutes of daylight today and 10 hours, 46 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 6:16 and sunrise is at 6:46. The moon is waning gibbous. Illumination was 74% at midnight, will be 70% at noon and 65% at midnight tonight. Moonset is at 11:20 this morning. Moonrise is at 21:46 tonight. Moonset is at 11:53 tomorrow morning. Moonlight time is 13 hours, 34 minutes which is 29 minutes less than yesterday.

Cool Fall began November 2 and runs for 29 days through November 30. High temperatures in this period are usually in the 30s, 40s and 50s. Highs in the 10s and 20s occur infrequently. Thanksgiving is in eight days.