January 2: ORD

Today is January 2nd. It's the 2nd day of the year. 364 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 33 and 19.

On the warm side, in 2004 the high was the record high of 61 with a low of 37. Four years before, in 2000, the high was the former record high of 60 with a low of 35. Before 2000, the record high was 58 in 1950. In 1997 the high was 53 with a low of 37. A year later, in 1998, the high was 50 with a low of 37. In 2005 the high was 54 with a low of 33. A year later, in 2006, the high was 42 with a low of 40, a two degree spread. In 1992 the high was 43 with a low of 36, a seven degree spread. The other warm high was 43 in 2007. The other warm low was 29 in 1987. The record warmest low of 47 was set way back in 1897, at a time when the official readings were taken adjacent to Lake Michigan. 21 of the past 33 highs (64%) were in the: 20s (8) and 30s (13). On the warm side, eight highs (24%) were in the: 40s (3), 50s (3) and 60s (2). Five of the nine years from 1997 through 2005 produced all of the highs in the 50s and 60s. On the cold side, four highs (12%) were in the: single digits (1) and 10s (a.k.a. teens) (3).

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 13 with a low of -4, a cold day. In 1977 the high was 19 with a low of 2, a cold day. In 1974 the high was 15 with a low of 1, a cold day. In 1969 the high was 22 with a cold low of 0, a cold day. In 1968 the high was 20 with a low of 16, a four degree spread. In 1966 the high was a warm 44 with a low of 27, a warm day. In 1965 the low was a warm 29 degrees. In 1963 the high was 31 with a low of 26, a five degree spread. In 1961 the high was 31 with a low of 24, a seven degree spread. In 1960 the high was 43 with a low of 31, a warm day.

More recently, we had small spreads of three degrees in 2003 (31/28), four degrees in 1994 (32/28), five degrees in 1980 (33/28) and seven degrees in 1987 (36/29).

On the cold side, in 1979 the high was 4 (O'Hare's coldest) with a low of -13 (O'Hare's coldest). The record low of -16 was set way back in 1879 and the record coldest high of 2 was set back in 1920. Both records were set at a time when the official readings were taken adjacent to Lake Michigan. In 1985 the high was 14 with a low of -3. Two years ago, in 2010, the high was 11 with a low of 2. Two years before that, in 2008, the high was 20 with a low of 2. In 2001 the high was 19 with a low of 5. The other cold low was 2 in 1988. 18 of the last 33 lows (55%) were in the: 10s (a.k.a. teens) (10) and 20s (8). On the cold side, eight lows (24%) were in the: negative 10s (a.k.a. negative teens) (1), negative single digits (1) and single digits (6). On the warm side, seven lows (21%) were in the: 30s (6) and 40s (1). Prior to 1979, O'Hare's coldest was -4 in 1978.

There were two instances of back-to-back years in which temperatures were just about as opposite as they can be. In the first instance, in 2000 the high was 60 with a low of 35, overall 23.5 degrees ABOVE normal. Then in 2001 the high was 19 with a low of 5, overall 12 degrees BELOW normal. In the second instance, in 2007 the high was 43 with a low of 26, overall 10.5 degrees ABOVE normal. Then in 2008, the high was 20 with a low of 2, overall 13 degrees BELOW normal.

Today is a major snow day in O'Hare's history. In 1999, 18.6 inches fell. This was the second day of a three day, 21.6 inch storm. This 18.6 inches was the most snow ever recorded in a calendar day in Chicago. This storm comprised 73% of the month's total of 29.6 inches.

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 16:32 and twilight ends at 17:04. There's a total of 9 hours, 10 minutes of daylight today and 10 hours, 13 minutes between twilights. We didn't gain any 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, having reached first quarter yesterday morning at 15 minutes past midnight. Illumination was 59% at midnight, will be 64% at noon and 68% at midnight tonight. Moonset was at 1:11 this morning. Moonrise is at 11:51 this morning. Moonset is at 2:11 tomorrow morning. Moonlight time is 10 hours, 40 minutes which is 32 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 14 days.