January 5: ORD

Today is January 5th. It's the 5th day of the year. 361 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 17.

On the warm side, in 1998 the high was the near-record high of 55 with a low of 40. The record high of 56 was set way back in 1890, at a time when the official readings were taken adjacent to Lake Michigan. In 2007 the high was 50 with the near-record warmest low of 42. The record warmest low of 44 was set back in 1946 at Midway. In 2008 the high was 43 (our most recent 40s high) with a low of 35. The other warm lows were 34 in 1992, 31 in 2006 and 30 in 2003. 18 of the past 33 highs (55%) were in the 30s. There were six consecutive 30s highs from 2001 through 2006. On the warm side, four highs (12%) were in the: 40s (2) and 50s (2). Until 1998, O'Hare's warmest high was 49 in 1966. On the cold side, 11 highs (33%) were in the: negative single digits (1), single digits (1), 10s (a.k.a. teens) (2) and 20s (7).

In looking back through the years to the first January at O'Hare in 1959, the following instances were notable. In 1978 the low was a warm 29 degrees. In 1977 the high was 30 with a low of 25, a five degree spread. In 1976 the low was a cold zero degrees. In 1974 the high was 20 with a cold low of 5, a cold day. In 1973 the high was 13 with a low of 5, a cold day. In 1972 the high was 10 with a low of -5, a cold day. In 1971 the high was 12 with a low of 0, a cold day. In 1970 the high was 18 with a low of -2, a cold day. In 1969 the high was 21 with a cold low of -4, a cold day. In 1968 the high was 28 with a cold low of -3, a 31 degree spread and cold day. In 1966 the high was a warm 49 degrees. In 1965 the high was 42 with a warm low of 31, a warm day. In 1963 the high was 33 with a low of 26, a seven degree spread. In 1962 the high was 40 with a warm low of 32, a warm day. In 1959 the high was 8 with a low of -13, a cold day.

More recently, we had small spreads of two degrees in 1992 (36/34), two degrees in 2003 (32/30), five degrees in 2005 (31/26), six degrees in 1983 (32/26), six degrees in 2006 (37/31) and seven degrees in 2002 (35/28).

On the cold side, in 1988 the high was -2 (O'Hare's coldest high) with a low of -11. In 1979 the high was 4 with a low of -11. Two decades later, in 1999, the high was 18 with the near-record low of -16, a 34 degree spread. The record low of -18 was set way back in 1884, at a time when the official readings were taken adjacent to Lake Michigan. In 1995 the high was 19 with a low of -1. In 1981 the high was 24 with a low of -2. The record coldest high of -5 was set back in 1924, at a time when the official readings were taken adjacent to Lake Michigan. The other cold lows were 4 degrees, in both 1986 and 2004. 19 of the last 33 lows (58%) were in the: 10s (a.k.a. teens) (7) and 20s (12). Our most recent 20s low was 26 in 2005. On the cold side, eight lows (24%) were in the: single digits (3), negative single digits (2) and negative 10s (a.k.a. negative teens) (3). Prior to 1979, O'Hare's coldest low was -13 in 1959. On the warm side, six lows (18%) were in the: 30s (4) and 40s (2).

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 1998 the high was 55 with a low of 40, overall 23.5 degrees ABOVE normal. Then in 1999 the high was 18 with a low of -16, overall 23 degrees BELOW normal.

Today is a major snow day in O'Hare's history. In 2005, 6.2 inches fell. This was the second day of a three day, 9.8 inch snowstorm. In 1962, 0.3 inches fell. This was the first day of a three day, 11 inch snowstorm.

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 16:35 and twilight ends at 17:07. There's a total of 9 hours, 13 minutes of daylight today and 10 hours, 16 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 84% at midnight, will be 88% at noon and 91% at midnight tonight. Moonset is at 4:07 this morning. Moonrise is at 13:39 this afternoon. Moonset is at 5:02 tomorrow morning. Moonlight time is 9 hours, 32 minutes which is 16 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 11 days.