June 14: ORD

Today is June 14th. It's the 166th day of the year. 200 days remain. It's week 24 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 79 and the normal low is 58. I've calculated the 33-year averages at 82 and 60.

On the hot side, in 1987 (O'Hare's warmest June 14th) the high was the record high of 99 with a low of 68, a 31 degree spread. The next year, 1988, the high was 94 with a low of 71. In 1981 the high was 88 with the record warmest low of 75. A decade later, in 1991, the high was 93 with a low of 69. The other hot highs were 94 in 1994 and 91 degrees in: 1983, 1992 and 2001 (our most recent 90s high). 29 of the past 33 highs (88%) were in the: 70s (10), 80s (11) and 90s (8). Four highs were in the cool 60s. Interestingly, the year after our most recent 90s high (91 in 2001), the high was just 67 in 2002. This also happened in 1983. The high that year was 91. The year later (1984), the high was just 69. All of the 90s highs (1979 onward) occurred from 1983 through 2001.

In looking back through the years to the first June at O'Hare in 1959, the following instances were notable: In 1978 the high was a cool 67 degrees. In 1969 the high was a cool 65 with a low of 49, a cool day. In 1967 the low was a warm 70 degrees. In 1963 the high was a cool 67 degrees. In 1962 the high was 77 with a low of 47, a 30 degree spread. In 1961 the high was a cool 65 degrees. In 1960 the high was a cool 60 with a low of 54, a six degree spread and cool day.

More recently, the additional spreads were large: 31 degrees in 1983 (91/60) and 31 degrees in 1995 (90/59).

On the cool side, in 1997 (O'Hare's coolest June 14th) the high was 68 with the record low of 45 (the former record low of 47 occurred in 1985). In 1986 the high was 65 with a low of 54. The other cool high was 67 in 2002. The record coolest high of 58 occurred way back in 1875, at a time when the official readings were taken adjacent to Lake Michigan. 29 of the last 33 lows (88%) were in the: 50s (14) and 60s (15). Two lows were in the cool 40s and two were in the warm 70s. There is a tie for O'Hare's second coolest June 14th. In 1960 the high was 60 (O'Hare's coolest high of the date) with a low of 54. Then in 1969 the high was 65 with a low of 49.

In regards to last year, 2011: the 45 degree drop in temperature from the high of 95 on 6/8/11 to the low of 50 late 6/9/11 was the greatest two-day drop in temperature since the June record drop of 49 degrees in 1988, 24 years ago. The drop in 1988 was from a high of 103 on June 25 to a low of 54 on June 26. The all-time record, irregardless of month, was a 61 degree drop from 74 degrees to 13 degrees on November 11 and 12, 1911. Data courtesy of The Chicago Weather Center Blog.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:42 and sunrise is at 5:16. Sunset is at 20:31 and twilight ends at 21:06. There's a total of 15 hours, 15 minutes of daylight today and 16 hours, 24 minutes between twilights. We gained no minutes of daylight from yesterday. Tomorrow twilight begins at 4:42 and sunrise is at 5:16. The moon is waning crescent. Illumination was 24% at midnight, will be 20% at noon and 17% at midnight tonight. Moonrise was at 2:03 this morning. Moonset is at 16:11 this afternoon. Moonrise is at 2:33 tomorrow morning. Moonlight time is 14 hours, 8 minutes which is 30 minutes longer than yesterday. 

Summer began on June 4th and runs for 110 days through September 21st. High temperatures in this period are usually in the 70s and 80s. Highs in the 90s and 100s occur infrequently. Flag Day is today. Father's Day is in three days.