March 29: ORD

Today is March 29th. It's the 89th day of the year. 277 days remain. It's week 13 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 52 and the normal low is 33. I've calculated the 33-year averages at 52 and 34.

On the warm side, in 1986 (O'Hare's warmest March 29th) the high was the record high of 88 with a low of 54, a 34 degree spread. In 1998 the high was 79 with a low of 44, a 35 degree spread. In 1981 the high was 63 with a low of 55 (O'Hare's warmest low of the date). The other warm highs were 71 in 2005 and 64 in 1993. The other warm low was 46 in 2007. The record warmest low of 63 was set way back in 1910, at a time when the official readings were taken adjacent to Lake Michigan. 15 of the past 33 highs (45%) were in the 40s. On the warm side, 16 highs (49%) were in the: 50s (6), 60s (7), 70s (2) and 80s (1). Prior to 1979, O'Hare's warm highs were 80 in 1963 and 71 in 1960. On the cold side, two highs (6%) were in the 30s.

In looking back through the years to the first March at O'Hare in 1959, the following instances were notable: In 1977 the high was 68 with a low of 51, a warm day. In 1976 the high was 60 with a warm low of 50, a warm day. In 1975 the high was a cold 35 with a low of 26, a cold day. In 1973 the high was 46 with a low of 42, a four degree spread. In 1972 the high was a cold 38 with a low of 31, a seven degree spread. In 1970 the high was 32 with a low of 19, a cold day. In 1969 the high was 28 with a low of 16, another cold day. In 1968 the high was a warm 66 degrees. In 1965 the high was 37 with a low of 21, a cold day. In 1964 the high was 28 with a low of 14, another cold day. What made 1964 even more notable was that 7.4 inches of snow fell as well. In 1963 the high was was a warm 80 with a low of 39, a warm day and a spread of 41 degrees. In 1962 the high was a warm 64 degrees. In 1960 the high was a warm 71 with a low of 40, a 31 degree spread and warm day.

More recently, we had small spreads of six degrees in 1990 (44/38), six degrees in 1995 (43/37) and seven degrees in 1992 (43/36). There were large spreads of 34 degrees in 1982 (60/26) and 38 degrees in 2005 (71/33).

On the cold side, in 1991 the high was 37 with a low of 24. In 2003 the high was 38 with a low of 26. The other cold high was 40 in 1983. The record low of 9 and record coldest high of 24 were set on the same cold day way back in 1887, at a time when the official readings were taken adjacent to Lake Michigan. 27 of the last 33 lows (82%) were in the: 20s (10) and 30s (17). O'Hare's coldest March 29th was in 1964 with a high of 28 and low of 14. The second coldest March 29th was in 1969 with a high of 28 and low of 16. These highs of 28 were O'Hare's only 20s highs of the date. O'Hare's only other sub-20s low of the date was 19 in 1970. Six lows were in the warm: 40s (4) and 50s (2). Prior to 1981, O'Hare's warm lows were 51 in 1977 and 50 in 1976.

Today is a major day in Chicago's snow history. In 1972 at O'Hare, 5.9 inches fell. At Midway, 6.5 inches fell. But Rockford takes the cake as 10.4 inches fell there.

Three years ago (in 2009) in Crystal Lake we had somewhere between 5 and 6 and a half inches of snow. The big event at my house was that our evergreen tree was uprooted by the storm and was draped across our driveway. Other amounts were: 6.8 inches at Bull Valley (close to Crystal Lake), 7.2 inches in Cary (close to Crystal Lake), 5.4 inches in St. Charles, 5 inches in DeKalb, 4.8 inches in Schaumburg, 3.8 inches in Elgin, 3 inches in Barrington, 2 inches in Harvard, 1.5 inches in Streamwood, 0.4 inches at Midway, 0.1 inches in Rockford and just a trace at O'Hare. It's kind of unique that all three major regional airports (O'Hare, Midway and Rockford) hardly had any snow. So it seems that conditions were just right that very specific locations got hit.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:12 and sunrise is at 6:40. Sunset is at 19:16 and twilight ends at 19:45. There's a total of 12 hours, 36 minutes of daylight today and 13 hours, 33 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:10 and sunrise is at 6:38. The moon is waxing crescent and will reach first quarter tomorrow at 14:41. Illumination was 35% at midnight, will be 40% at noon and 45% at midnight tonight. Moonset was at 1:13 this morning. Moonrise is at 10:44 this morning. Moonset is at 1:59 tomorrow morning. Moonlight time is 14 hours, 29 minutes which is one minute shorter than yesterday.

Spring began on March 12th and runs for 84 days through June 3rd. Cool Spring began on March 12th and runs for 32 days through April 12th. High temperatures in this period are usually in the 30s, 40s and 50s. Highs in the 60s and 70s usually occur infrequently. April Fools' Day and Palm Sunday are in three days. Good Friday is in eight days. Easter is in ten days.