March 2: ORD

Today is March 2nd. It's the 62nd day of the year. 304 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 41 and the normal low is 25. I've calculated the 33-year averages at 39 and 23.

On the warm side, in 1983 the high was 65 with a low of 30, a 35 degree spread. In 1992 the high was 58 with a low of 32. In 2008 the high was 57 with a low of 32. The other warm low was 39 in 2004. The record high of 71 was set in 1974 and the record warmest low of 44 occurred the prior year, in 1973. Both records were set at Midway. 22 of the past 33 highs (67%) were in the: 30s (12) and 40s (10). O'Hare had eight consecutive 30s & 40s highs from 1997 through 2004. Our most recent 40s high was 48 in 2004. On the warm side, five highs (15%) were in the: 50s (4) and 60s (1). O'Hare's warmest March 2nd was in 1974 when the high was 68 (the warmest) and low was 45 (the warmest). O'Hare's other pre-1979 warm highs were 63 in 1961 and 58 in 1966. On the cold side, six highs (18%) were in the 20s. O'Hare's coldest highs were 21 degrees in 1972 and 1980.

In looking back through the years to the first March at O'Hare in 1959, the following instances were notable: In 1978 the high was 25 with a low of 10, a cold day. In 1976 the high was 43 with a warm low of 38, a five degree spread. In 1975 the high was 30 with a cold low of 13, a cold day. In 1974 the high was 68 with a low of 45, a warm day and year of the record high of 71 (at Midway). In 1973 the high was 52 with a warm low of 41, a warm day and year of the record warmest low of 44 (at Midway). In 1972 the high was 21 with a low of 11, a cold day. In 1970 the high was 43 with low of 36, a seven degree spread. In 1966 the high was a warm 58 with a low of 28, a 30 degree spread. In 1963 the low was a cold 13 degrees. In 1962 the high was 22 with a low of 10, a cold day. In 1961 the high was a warm 63 with a low of 30, a 33 degree spread and warm day. In 1960 the high was 27 with a low of 12, a cold day.

More recently, we had small spreads of six degrees in 1979 (37/31) and seven degrees in 2007 (32/25).

On the cold side, in 1980 (O'Hare's coldest March 2nd) the high was 21 with a low of -1. In 1996 the high was 28 with a low of 2. The year earlier, 1995, the high was 28 with a low of 7. Three years ago, in 2009, the high was 22 with a low of 14. Four years prior, in 2005, the high was 27 with a low of 13. Two years before that, in 2003, the high was 32 with a low of 10. In 1989 the high was 27 with a low of 15. The other cold low was 11 in 1994. The record low of -4 was set in 1913, at a time when the official readings were taken adjacent to Lake Michigan. The record coldest high of 10 occurred three decades later in 1943 at Midway. 23 of the last 33 lows (70%) were in the: 20s (14) and 30s (9). O'Hare had six consecutive lows in the 20s & 30s from 1997 through 2002. Seven lows (21%) were in the cold 10s (a.k.a. teens). Three lows (9%) were in the very cold: negative single digits (1) and single digits (2).

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 2008 the high was 57 with a low of 32, overall 11.5 degrees ABOVE normal. Then in 2009 the high was 22 with a low of 14, overall 15 degrees BELOW normal.

Today is a major day in Chicago's snow history. In 2002, 7.1 inches fell. This was the second of four days in which a total of 10.2 inches fell. This was 91% of the month's total of 11.2 inches. In 1982, 3.5 inches fell. This was the first of three days in which 12.1 inches fell. In 1954 at Midway, 11.5 inches fell. In 1948 at Rockford, 13.0 inches fell.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:58 and sunrise is at 6:26. Sunset is at 17:45 and twilight ends at 18:13. There's a total of 11 hours, 19 minutes of daylight today and 12 hours, 15 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 5:57 and sunrise is at 6:25. The moon is waxing gibbous, having reached first quarter two nights ago at 19:21. Illumination was 62% at midnight, will be 66% at noon and 71% at midnight tonight. Moonset is at 2:21 this morning. Moonrise is at 11:52 this morning. Moonset is at 3:06 tomorrow morning. Moonlight time is 14 hours, 29 minutes which is four 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 15 days.