March 19: ORD

Today is March 19th. It's the 79th day of the year. 287 days remain. It's week 12 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 48 and the normal low is 30. I've calculated the 33-year averages at 47 and 30.

On the warm side, in 1979 (O'Hare's second warmest March 19th) the high was 63 with a low of 55 (O'Hare's warmest low of the date). Two years ago, in 2010 (O'Hare's fifth warmest March 19th), the high was 65 with a low of 39. The other warm highs were 63 in 1985 and 61 in 2007. The other warm low was 45 in 1995. The record high of 78 was set back in 1921. The record warmest low of 59 occurred way back in 1903. Both records were set at a time when the official readings were taken adjacent to Lake Michigan. 29 of the past 33 highs (88%) were in the: 30s (9), 40s (11) and 50s (9). Our most recent 30s high was 39 in 1998. On the warm side, four highs were in the 60s. O'Hare's warmest March 19th was in 1976 with a high of 76 (O'Hare's warmest reading of the date) and low of 51. The second warmest was 1979 (mentioned above). The third warmest was in 1968 with a high of 62 and low of 44. The fourth warmest was in 1959 with a high of 65 and low of 40. Another pre-1979 warm high was 61 in 1969.

In looking back through the years to the first March at O'Hare in 1959, the following instances were notable: In 1976 the high was 76 with a low of 51, a warm day. Also in 1976, the temperature fell to 25 degrees on the 21st, a huge 51 degree drop! In 1969 the high was a warm 61 degrees. In 1968 the high was 62 with a low of 44, a warm day. In 1965 the high was 19 with a low of 7, a cold day. In 1959 the high was a warm 65 with a low of 40, a warm day.

More recently, we had small spreads of three degrees in 1983 (35/32), four degrees in 1982 (39/35), five degrees in 1984 (33/28), five degrees in 1998 (39/34), six degrees in 1996 (38/32) and six degrees in 2000 (42/36). There was a large spread of 35 degrees in 1986 as the high was 53 with a low of 18.

On the cold side, in 1990 the high was 31 with a low of 21. A year before, in 1989, the high was 37 with a low of 15. In 1981 the high was 32 with a low of 20. The other cold low was 18 in 1986. The other cold highs were 33 in 1984, 33 in 1993 and 35 in 1983. The record low of 0 and record coldest high of 17 were set on the same cold day back in 1923, at a time when the official readings were taken adjacent to Lake Michigan. 29 of the last 33 lows (88%) were in the: 20s (14) and 30s (15). Two lows were in the cold 10s (a.k.a. teens). O'Hare's coldest March 19th was in 1965 with a high of 19 and low of 7. Two lows were in the warm: 40s (1) and 50s (1).

Today is a major day in Chicago's snow history. In 1983 at O'Hare, this was the first day of a three day storm which produced 7.2 inches. Today 0.9 inches fell.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 6:30 and sunrise is at 6:57. Sunset is at 19:05 and twilight ends at 19:33. There's a total of 12 hours, 8 minutes of daylight today and 13 hours, 3 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 6:28 and sunrise is at 6:56. The moon is waning crescent. Illumination was 11% at midnight, will be 8% at noon and 6% at midnight tonight. Moonrise is at 5:12 this morning. Moonset is at 16:31 this afternoon. Moonrise is at 5:40 tomorrow morning. Moonlight time is 11 hours, 19 minutes which is 34 minutes longer than yesterday. The Spring Equinox is at 0:14 tomorrow morning.

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 13 days.