January 11: ORD

Today is January 11th. It's the 11th day of the year. 355 days remain. It's week 2 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 16. I've calculated the 33-year averages at 31 and 17.

On the warm side, in 2007 the high was 45 with a low of 35. A year earlier, in 2006, the high was 42 with a low of 37 (O'Hare's warmest low of the date) and a small five degree spread. In 2002 the high was 43 with a low of 33. In 1990 the high was 42 with a low of 32. The other warm highs were 54 in 1980 (O'Hare's warmest high of the date), 45 in 1992 and 44 in 1989. The other warm lows were 30 in 2005, 29 in 2000 and 28 in 2008. The record high of 61 was set way back in 1880 and the record warmest low of 40 was set way back in 1890. Both records were set at a time when the official readings were taken adjacent to Lake Michigan. 27 of the past 33 highs (82%) were in the: 20s (9), 30s (10) and 40s (8). On the warm side, one high was in the 50s (54 in 1980). On the cold side, five highs were in the: single digits (2) and 10s (a.k.a. teens) (3). Prior to 1979, O'Hare had single digit highs of 5 in 1977 and 8 in 1962.

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 18 with a low of -6, a cold day. In 1977 the high was 5 with a low of -11, a cold day. 1977 was the year of the record low (also -11 at Midway). In 1975 the high was a warm 45 with a low of 6, a 39 degree spread. In 1974 the high was 21 with a cold low of 4, a cold day. In 1973 the high was a cold 19 degrees. In 1969 the high was 13 with a low of -4, a cold day. In 1968 the high was 26 with a low of 20, a six degree spread. In 1963 the high was 30 with a low of 26, a four degree spread. In 1962 the high was 8 with a low of -13, a cold day. In 1961 the high was a warm 46 degrees. In 1960 the high was 37 with a warm low of 30, a seven degree spread.

More recently, we had six days of small spreads. One was four degrees: 28/24 in 1996. One was five degrees: 27/22 last year, in 2011. Three others were six degrees: 32/26 in 1991, 29/23 in 1993 and 36/30 in 2005. One was seven degrees: 20/13 three years ago, in 2009. The large spread was 39 degrees in 1980 (54/15).

On the cold side, in 1979 the high was 13 with a low of -16 (O'Hare's coldest low of the date). The official record low of -11 was set in 1977 because the low at Midway in 1979 was just a degree short at -10. That record low of -11 was initially set way back in 1887 and tied the very next year in 1888. Other area low temperatures in 1979 were: -24 at Rockford, -20 at Aurora, -26 at Barrington, -22 at DeKalb, -18 at Elgin, -29 at Marengo (just west of Crystal Lake) and -25 at Wheaton. In 1982 the high was the record coldest high of 4 with a low of -4. In 1997 the high was 6 (our most recent single digit high) with a low of -4. Two years after that, in 1999, the high was 13 (our most recent 10s high) with a low of -3 (our most recent below zero low). In 1981 the high was 14 with a low of -2. Three years later, in 1984, the high was 21 with a low of -2. 14 of the last 33 lows (43%) were in the 20s. 14 lows (42%) were in the cold: negative 10s (1), negative single digits (5), single digits (3) and 10s (a.k.a. teens) (5). O'Hare's most recent single digit low was 8 in 2003. Five lows (15%) were in the warm 30s. Until 1979, O'Hare's coldest lows were -13 in 1962 and -11 in 1977.

Today is a major day in O'Hare's snow history. In 1979, 0.2 inches fell. This was the first day of a 21.7 inch, seven day storm.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:50 and sunrise is at 7:21. Sunset is at 16:41 and twilight ends at 17:13. There's a total of 9 hours, 20 minutes of daylight today and 10 hours, 23 minutes between twilights. We gained a minute of daylight from yesterday. Tomorrow twilight begins at 6:50 and sunrise is at 7:21. The moon is waning gibbous, having reached the full Wolf (a.k.a. Old) moon two mornings ago at 0:15. Illumination was 96% at midnight, will be 93% at noon and 90% at midnight tonight. Moonset is at 8:30 this morning. Moonrise is at 19:43 tonight. Moonset is at 9:00 tomorrow morning. Moonlight time is 11 hours, 13 minutes which is 35 minutes longer 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 five days.