March 14: ORD

Today is March 14th. It's the 74th day of the year. 292 days remain. It's week 11 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 46 and the normal low is 29. I've calculated the 33-year averages at 47 and 29.

On the warm side, in 1990 (still O'Hare's warmest March 14th) the high was 69 with the record warmest low of 60. Five years later, in 1995 (until this year was the second warmest), the high was the record high (until the new record high of 81 in 2012) of 77 with a low of 43, a 34 degree spread. In 2002 the high was 63 with a low of 37. The other warm highs were 62 in 1989, 61 in 2007, 60 in 1996 and 58 in 2000. 25 of the past 33 highs (76%) were in the: 30s (8), 40s (9) and 50s (8). Our most recent 30s high was 36 in 2005. On the warm side, six highs (18%) were in the: 60s (5) and 70s (1). Until this year (2012): 1973 was the third warmest (70/49), 1971 was the fourth warmest (63/50) and 1977 was the fifth warmest (66/46). The other pre-1979 warm high was 59 in 1964. On the cold side, two highs (6%) were in the 20s. Prior to 1979, the only 20s high was 29 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 38 with a low of 34, a four degree spread. In 1977 the high was 66 with a low of 46, a warm day. In 1973 the high was 70 with a low of 49, a warm day. In 1971 the high was 63 with a low of 50, a warm day. In 1967 the high was 37 with a low of 34, a three degree spread. In 1965 the high was a cold 34 degrees. In 1964 the high was a warm 59 degrees. In 1962 the high was a cold 29 with a low of 23, a six degree spread. In 1960 the high was 32 with a low of 10, a cold day.

More recently, we had other large spreads were 32 degrees in 2003 (55/23) and 30 degrees in 1989 (62/32).

On the cold side, in 1993 (O'Hare's coldest March 14th) the high was 23 with the record low of 7. The record low of 7 also occurred way back in 1891. In 1988 the high was 28 with a low of 20. In 1979 the high was 32 with a low of 18. The other cold highs were 33 in both 1997 and 1998. The record coldest high of 18 occurred way back in 1895, at a time when the official readings were taken adjacent to Lake Michigan. 28 of the last 33 lows (85%) were in the: 20s (17) and 30s (11). O'Hare had consecutive highs in the 20s & 30s as follows: ten years from 1980 through 1989 and 14 years from 1996 through 2009. That's 24 of the 28 lows in the 20s & 30s or 86% of them! Two lows were in the cold: single digits (1) and 10s (a.k.a. teens) (1). Prior to 1979, the coldest low was 10 in 1960, part of O'Hare's second coldest March 14th (the high was 32). On the warm side, three lows were in the: 40s (2) and 60s (1). There haven't been any lows in the 50s since 50 in 1971.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:38 and sunrise is at 7:06. Sunset is at 18:59 and twilight ends at 19:27. There's a total of 11 hours, 53 minutes of daylight today and 12 hours, 49 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:36 and sunrise is at 7:04. The moon reaches last quarter tonight at 20:25. Illumination was 59% at midnight, will be 54% at noon and 48% at midnight tonight. Moonrise is at 1:42 this morning. Moonset is at 11:10 this morning. Moonrise is at 2:39 tomorrow morning. Moonlight time is 9 hours, 28 minutes which is nine minutes 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. St. Patrick's Day is in three days.