March 1: ORD

Today is March 1st. It's the 61st day of the year. 305 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 25. I've calculated the 33-year averages at 41 and 26.

On the warm side, in 1992 (O'Hare's warmest March 1st) the high was the record high of 71 with a low of 38, a 33-degree spread. In 2004 the high was 62 with the co-record warmest low of 45. In 1991 the high was 51 with the other co-record warmest low of 45, a six degree spread. In 2000 the high was 56 (our most recent 50s high) with a low of 36. Three years earlier, in 1997, the high was 55 with a low of 33. The other warm highs were 56 in 1983 and 52 in 1988. 21 of the past 33 highs (64%) were in the: 30s (11) and 40s (10). On the warm side, seven highs (21%) were in the: 50s (5), 60s (1) and 70s (1). The pre-1979 warm highs were 58 in 1965 and 57 in 1972. On the cold side, five highs (15%) were in the: 10s (a.k.a. teens) (1) and 20s (4). O'Hare's coldest high of the date was 17 in 1962.

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 a cold 28 degrees. In 1976 the high was 40 with a low of 35, a five degree spread. In 1975 the high was a cold 28 degrees. In 1973 the low was a warm 37 degrees. In 1972 the high was a warm 57 with a low of 19, a 38 degree spread. In 1970 the high was 38 with a low of 32, a six degree spread. In 1968 the high was 51 with a low of 15, a 36 degree spread. In 1967 the high was 35 with a cold low of 3, a 32 degree spread and cold day. In 1965 the high was 58 with a low of 39, a warm day. 1965 was also the year of the former record warmest low of 43, set at Midway. In 1963 the high was 34 with a cold low of 3, a 31 degree spread and cold day. In 1962 the high was 17 with a low of -8, a cold day and year of the record low of -5 at Midway. In 1960 the high was 23 with a low of 0, another cold day.

More recently, we had small spreads of four degrees in 1981 (35/31) and six degrees in 1998 (38/32). The lone large spread was 33 degrees in 1983 (56/23).

On the cold side, in 1980 the high was 19 with a low of 8. In 1995 the high was 23 with a low of 10. In 1989 the high was 23 with a low of 11. Two decades later (and three years ago), in 2009, the high was 22 with a low of 14. The other cold high was 27 in 2005. The record low of -5 was set in 1962 at Midway. The record coldest high of 14 occurred way back in 1890, at a time when the official readings were taken adjacent to Lake Michigan. 24 of the last 33 lows (73%) were in the: 20s (12) and 30s (12). O'Hare had seven consecutive lows in the 20s & 30s from 1997 through 2003. Seven lows (21%) were in the cold: single digits (1) and 10s (a.k.a. teens) (6). Two lows (6%) were in the warm 40s. O'Hare's coldest March 1st was in 1962 when the high was 17 and low was -8. The other pre-1979 cold lows were 0 in 1960, 3 in 1963 and 3 in 1967.

Today is a major day in Chicago's snow history. In 2002, 2.0 inches fell. This was the first of four days in which a total of 10.2 inches fell. This was 91% of the month's total of 11.2 inches.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:00 and sunrise is at 6:28. Sunset is at 17:44 and twilight ends at 18:12. There's a total of 11 hours, 16 minutes of daylight today and 12 hours, 12 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 5:58 and sunrise is at 6:26. The moon is waxing gibbous, having reached first quarter last night at 19:21. Illumination was 52% at midnight, will be 57% at noon and 62% at midnight tonight. Moonset is at 1:32 this morning. Moonrise is at 10:59 this morning. Moonset is at 2:21 tomorrow morning. Moonlight time is 14 hours, 33 minutes which is seven 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. St. Patrick's Day is in 16 days.