January 27: ORD

Today is January 27th. It's the 27th day of the year. 339 days remain. It's week 4 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 15.

On the warm side, in 2002 the high was 59 (O'Hare's warmest of the date) with a low of 38 (O'Hare's warmest of the date). Four years later, in 2006, the high was 51 (our most recent 50s high) with a low of 35. In 1999 the high was 49 with a low of 34. In 1990 the high was 50 with a low of 25. A year earlier, in 1989, the high was 48 with a low of 26. The other warm low was 30 in 1998. The record high of 62 was set in 1916, at a time when the official readings were taken adjacent to Lake Michigan. The record warmest low of 47 was set in 1944 at Midway. 26 of the past 33 highs (79%) were in the: 20s (13) and 30s (13). O'Hare had eight consecutive 20s & 30s highs from 1991 through 1998. On the warm side, five highs were in the: 40s (2) and 50s (3). On the cold side, two highs were in the: single digits (1) and 10s (a.k.a. teens) (1). O'Hare's coldest highs of the date are 5 in 1986, 6 in 1963, 7 in 1961 and 8 in 1971.

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 10 with a low of 4, a six degree spread and cold day. In 1977 the high was 19 with a low of -3, a cold day. In 1976 the high was 14 with a low of -3, a cold day. In 1974 the low was a warm 29 degrees. In 1973 the high was 46 with a low of 36, a warm day. In 1972 the high was 13 with a low of 3, a cold day. In 1971 the high was 8 with a low of -3, a cold day. In 1970 the high was 36 with a warm low of 32, a four degree spread. In 1968 the high was 45 with a low of 37, a warm day. In 1966 the high was 20 with a cold low of -8, a cold day. In 1965 the low was a cold 2 degrees. In 1963 the high was 6 with a low of -10, a cold day. In 1961 the high was 7 with a low of -5, a cold day. In 1960 the high was 34 with a warm low of 32, a small two degree spread. In 1959 the high was 23 with a cold low of -1, a cold day.

More recently, there were small spreads of six degrees in 1998 (36/30) and seven degrees in 1992 (33/26).

On the cold side, in 1986 the high was 5 (O'Hare's coldest high of the date) with a low of -6. In 2003 the high was 20 with a low of -7. In 1988 the high was 20 with a low of -7. In 1980 the high was 11 with a low of 3. The record low of -10 was set in 1955 at Midway. The record coldest high of -1 was set way back in 1895, at a time when the official readings were taken adjacent to Lake Michigan. 26 of the last 33 lows (79%) were in the: single digits (7), 10s (a.k.a. teens) (12) and 20s (7). Three lows were in the cold negative single digits. O'Hare's coldest reading of the date was -10 in 1963. Four lows were in the warm 30s. Until 2002 (low of 38), O'Hare's warmest low was 37 in 1968. Although there's been seven lows in the 20s, our most recent instance was 20 in 1994.

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 1988 the high was 20 with a low of -7, overall 17.5 degrees BELOW normal. Then in 1989 the high was 48 with a low of 26, overall 13 degrees ABOVE normal. In the second instance, in 2002 the high was 59 with a low of 38, overall 24.5 degrees ABOVE normal. Then in 2003 the high was 20 with a low of -7, overall 17.5 degrees BELOW normal.

Today is a major day in O'Hare's snow history. In 1967, 7 inches fell. This was the second day of a two day, 20.4 inch period of snow known as the Blizzard of '67. This paralyzed Chicago for a few days. Midway Airport reported 6.6 inches this day, part of a two day total of 23 inches. This comprised 80% of Midway's snow for the month. Midway also had 19.8 inches in a 24-hour period, a record.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:42 and sunrise is at 7:12. Sunset is at 17:01 and twilight ends at 17:31. There's a total of 9 hours, 49 minutes of daylight today and 10 hours, 49 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:41 and sunrise is at 7:11. The moon is waxing crescent. Illumination was 16% at midnight, will be 20% at noon and 24% at midnight tonight. Moonrise is at 9:00 this morning. Moonset is at 21:58 tonight. Moonrise is at 9:26 tomorrow morning. Moonlight time is 12 hours, 58 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. National Freedom Day is in five days. Groundhog Day is in six days.