February 28: ORD

Today is February 28th. It's the 59th day of the year. 307 days remain. It's week 9 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. ORD has been the official site of record for Chicago since Thursday, January 17, 1980. Before this, the official site of record 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 40 and the normal low is 24. I've calculated the 33-year averages at 38 and 22.

On the warm side, in 2000 the high was 55 with a low of 30. In 1983 the high was 56 with a low of 28. The other warm high was 55 in 2004, our most recent 50s high. O'Hare's warmest low of the date was 37 in 1987. The record high of 61 and record warmest low of 46 were both set on the same warm day way back in 1895, at a time when the official readings were taken adjacent to Lake Michigan. 22 of the past 33 highs (67%) were in the: 30s (11) and 40s (11). O'Hare registered nine consecutive highs in the 30s & 40s from 1987 through 1995. Our most recent 40s high was 40 in 2003. On the warm side, four highs (12%) were in the 50s. O'Hare's warmest day of the date was in 1976 when the high was 55 with a low of 34. O'Hare's warmest high was 57 in 1965. There was also a high of 54 in 1974. On the cold side, seven highs (21%) were in the 20s.

In looking back through the years to the first February at O'Hare in 1959, the following instances were notable: In 1976 the high was a warm 55 with a low of 34, a warm day. In 1974 the high was a warm 54 degrees. In 1967 the high was 28 with a low of 11, a cold day. In 1966 the high was 38 with a low of 34, a four degree spread. In 1965 the high was a warm 57 with a low of 21, a 36 degree spread. In 1963 the high was 30 with a cold low of 4 degrees, a cold day. In 1962 the high was 23 with a low of 0, a cold day. In 1960 the high was a cold 26 degrees. In 1959 the high was 39 with a low of 32, a seven degree spread.

More recently, we had small spreads of five degrees in 1984 (28/23), six degrees in 1987 (43/37), six degrees in 1999 (40/34), six degrees two years ago, in 2010 (38/32), seven degrees in 2007 (35/28) and seven degrees three years ago, in 2009 (27/20). The lone large spread was 30 degrees in 2004 (55/25).

On the cold side, in 1986 the high was 25 with a low of 8. In 2008 the high was 26 with a low of 8. In 2001 the high was 28 with a low of 11. In 1996 the high was 26 with a low of 14. Three years prior, in 1993, the high was 31 with a low of 9. The other cold highs were 27 three years ago in 2009, 28 in 1980 and 28 in 1984. The record low of 0 was set way back in 1884 and the record coldest high of 14 occurred way back in 1891. Both records were set 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) (10) and 20s (12). Our most recent 10s (or teens) low was 13 in 2003. O'Hare registered seven consecutive lows in the 10s & 20s from 2001 through 2007. Eight lows (24%) were in the warm 30s. Three lows (9%) were in the cold single digits. O'Hare's coldest day was in 1962 as the high was 23 with a low of 0.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:03 and sunrise is at 6:31. Sunset is at 17:42 and twilight ends at 18:10. There's a total of 11 hours, 11 minutes of daylight today and 12 hours, 7 minutes between twilights. We gained four minutes of daylight from yesterday. Tomorrow twilight begins at 6:01 and sunrise is at 6:29. The moon is waxing crescent. Illumination was 33% at midnight, will be 38% at noon and 42% at midnight tonight. Moonrise is at 9:30 this morning. Moonset is at 0:38 tomorrow morning. Moonrise is at 10:12 tomorrow morning. Moonlight time is 14 hours, 30 minutes which is 17 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. St. Patrick's Day is in 18 days.