January 6: ORD

Today is January 6th. It's the 6th day of the year. 360 days remain. It's week 1 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. Observations have been official at O'Hare 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 31 and the normal low is 17. I've calculated the 33-year averages at 31 and 18.

On the warm side, in 2008 the high was the record high of 60 with the record warmest low of 41. The former record high of 54 and former record warmest low of 40 both occurred in 1907, at a time when the official readings were taken adjacent to Lake Michigan. In 1998 the high was 47 with our most recent 30s low of 39. In 1987 the high was 48 with a low of 34. A couple of years later, in 1989, the high was 37 with a low of 34, a three degree spread. In 2007 the high was 42 with a low of 29. Another warm low was 32 in 1992. 23 of the past 33 highs (70%) were in the: 20s (9) and 30s (14). On the warm side, six highs (18%) were in the: 40s (5) and 60s (1). O'Hare's warmest high (until 2008) was 49 in 1965. There have been no 50s highs in O'Hare's history for the date. On the cold side, four highs (12%) were in the: single digits (2) and 10s (a.k.a. teens) (2).

In looking back through the years to the first January at O'Hare in 1959, the following instances were notable: in 1978 the high was 37 with a warm low of 34, a three degree spread and warm day. In 1975 the high was 37 with a warm low of 33, a four degree spread. In 1974 the high was a cold 18 degrees with a low of 6, a cold day. In 1973 the high was 18 with a low of 3, a cold day. In 1971 the high was 7 with a low of -4, a cold day. In 1970 the high was 8 with a low of -11, a cold day. In 1968 the high was 13 with a low of -3, a cold day. In 1967 the high was a warm 43 degrees. In 1966 the high was 31 with a low of 26, a five degree spread. In 1965 the high was 49 with a low of 32, a warm day. In 1963 the high was 29 with a low of 24, a five degree spread. In 1961 the high was 44 with a low of 30, a warm day. In 1959 the high was 23 with a cold low of 1, a cold day.

More recently, we had small spreads of three degrees in 2006 (31/28), five degrees in 1992 (37/32), seven degrees in 1994 (33/26) and seven degrees in 2003 (33/26).

On the cold side, in 1988 the high was 2 with the record low of -14. The record low of -14 was first set way back in 1884, at a time when the official readings were taken adjacent to Lake Michigan. In 1979 the high was 10 with a low of -11. In 2004 the high was 9 with a low of -3. In 1986 the high was 14 with a low of -3. In 1999 the high was 21 with a low of 2. The record coldest high of -1 was set way back in 1912, at a time when the official readings were taken adjacent to Lake Michigan. 22 of the last 33 lows (67%) were in the: 10s (a.k.a. teens) (13) and 20s (9). On the cold side, six lows (18%) were in the: negative 10s (2), negative single digits (2) and single digits (2). On the warm side, five lows (15%) were in the: 30s (4) and 40s (1). Prior to 1979, O'Hare had a very cold low of -11 in 1970.

There were three instances of back-to-back years in which temperatures were just about as opposite as they can be. In the first instance, in 1986 the high was 14 with a low of -3, overall 18.5 degrees BELOW normal. Then in 1987 the high was 48 with a low of 34, overall 17 degrees ABOVE normal. In the second instance, in 1988 the high was 2 with a low of -14, overall 30 degrees BELOW normal. Then in 1989 the high was 37 with a low of 34, overall 11.5 degrees ABOVE normal. In the third instance, in 1998 the high was 47 with a low of 39, overall 19 degrees ABOVE normal. Then in 1999 the high was 21 with a low of 2, overall 12.5 degrees BELOW normal.

Today is a major snow day in O'Hare's history. In 2005, 2.4 inches fell. This was the third day of a three day, 9.8 inch snowstorm. In 1962, 8.6 inches fell. This was the second day of a three day, 11 inch snowstorm. In 1918 at the U.S. Courthouse in Chicago, a whopping 14.4 inches fell today. That was 94 years ago!

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:51 (the latest start to twilight) and sunrise is at 7:22 (the latest sunrise of the year). Sunset is at 16:36 and twilight ends at 17:08. There's a total of 9 hours, 14 minutes of daylight today and 10 hours, 17 minutes between twilights. We gained a minute of daylight from yesterday. Tomorrow twilight begins at 6:51 (the latest start to twilight) and sunrise is at 7:22 (the latest sunrise of the year). The moon is waxing gibbous. Illumination was 91% at midnight, will be 93% at noon and 96% at midnight tonight. Moonset was at 5:02 this morning. Moonrise was at 14:26 this afternoon. Moonset is at 5:54 tomorrow morning. Moonlight time is 9 hours, 24 minutes which is eight minutes shorter than yesterday.

Winter began December 1st and runs for 102 days through March 11th. High temperatures in this period are usually in the 20s and 30s. Highs in the 40s and 50s occur infrequently. Martin Luther King, Jr. Day is in ten days.