April 14: ORD

Today is April 14th. It's the 105th day of the year. 261 days remain. It's week 15 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. From Friday, January 1, 1926 through Tuesday, June 30, 1942, the official site was at the University of Chicago. 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 58 and the normal low is 38. I've calculated the 33-year averages at 60 and 39.

On the warm side, in 2006 (O'Hare's warmest April 14th) the high was 81 with the record tying warmest low of 63. The record warmest low of 63 was originally set way back in 1883. Three years before, in 2003, the high was the record high of 85 with a low of 48, a 37 degree spread. The former record high of 83 occurred in 1941. Two years ago, in 2010, the high was 80 with a low of 46, a 34 degree spread. The other warm highs were 77 in 2002, 76 in 2000 and 71 in 1994. 22 of the past 33 highs (67%) were in the: 50s (14) and 60s (8). O'Hare's most recent 60s high was 63 in 2005. There were 11 consecutive highs in the 50s & 60s from 1981 through 1991. 8 of these 11 (73%) were in the 50s. On the warm side, six highs (18%) were in the: 70s (3) and 80s (3). Prior to 1979, O'Hare's warmest April 14th was in 1967 as the high was 74 with a low of 58. O'Hare also had a high of 80 in 1976. On the cold side, five highs (15%) were in the: 30s (1) and 40s (4). 

In looking back through the years to the first April at O'Hare in 1959, the following instances were notable: In 1976 the high was a warm 80 with a low of 47, a 33 degree spread and warm day. In 1967 the high was 74 with a low of 58, a warm day. In 1966 the high was 59 with a low of 27, a 32 degree spread. In 1963 the high was 59 with a low of 28, a 31 degree spread. In 1962 the high was a cold 45 degrees. In 1960 the low was a warm 54 degrees.

More recently, we had additional large spreads of 39 degrees in 2004 (68/29), 36 degrees in 2000 (76/40), 36 degrees in 2002 (77/41) and 30 degrees in 2005 (63/33).
 
On the cold side, in 1980 (O'Hare's coldest April 14th) the high was 35 (O'Hare's coldest high of the date) with a low of 31, a four degree spread. In 1996 the high was 44 with a low of 33. The other cold highs were 44 three years ago, in 2009 and 46 in 1992. The record low of 23 was set way back in 1907 and tied in 1943 at Midway. The record coldest high of 32 was set way back in 1893, at a time when the official readings were taken adjacent to Lake Michigan. 30 of the last 33 lows (91%) were in the: 30s (16) and 40s (14). Two lows were in the cold 20s. O'Hare's coldest lows were 27 in 1966, 28 in 1963, 29 in 1997 and 29 in 2004. One low was in the warm 60s. O'Hare's most recent 50s low was 58 in 1967. The low was also 54 in 1960. 

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:44 and sunrise is at 6:13. Sunset is at 19:34 and twilight ends at 20:03. There's a total of 13 hours, 21 minutes of daylight today and 14 hours, 19 minutes between twilights. We gained three minutes of daylight from yesterday. Tomorrow twilight begins at 5:43 and sunrise is at 6:12. The moon is waning crescent, having reached last quarter yesterday at 5:50. Illumination was 42% at midnight, will be 37% at noon and 32% at midnight tonight. Moonrise was at 2:44 this morning. Moonset was at 13:21 this afternoon. Moonrise is at 3:15 tomorrow morning. Moonlight time is 10 hours, 37 minutes which is 29 minutes longer than yesterday. 

Spring began on March 12th and runs for 84 days through June 3rd. Warm Spring began yesterday, on April 13th and runs for 52 days through June 3rd. High temperatures in this period are usually in the 50s, 60s and 70s. Highs in the 80s and 90s usually occur infrequently. Earth Day is in eight days.