June 26: ORD

Today is June 26th. It's the 178th day of the year. 188 days remain. It's week 26 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 83 and the normal low is 62. I've calculated the 33-year averages at 84 and 62.

On the hot side, in 1983 (tied with 1969 as O'Hare's warmest June 26th) the high was the record high of 99 with a low of 72. In 2005 the high was 93 with a low of 70. Two years later, in 2007, the high was 92 with a low of 70. The record warmest low of 77 occurred back in 1931 at the University of Chicago. 25 of the past 33 highs (76%) were in the: 70s (9) and 80s (16). O'Hare recorded 13 consecutive 70s & 80s highs from 1992 through 2004. Seven highs (21%) were in the hot 90s. One high (3%) was in the cool 60s (69 in 1982). That only 60s high was followed the next year by our record high of 99 in 1983. In 1969 (tied with 1983 as the warmest June 26th) the high was 96 (O'Hare's second hottest high of the date) with a low of 75 (O'Hare's warmest low of the date). 

In looking back through the years to the first June at O'Hare in 1959, the following instances were notable: In 1977 the high was 89 with a low of 58, a 31 degree spread. In 1974 the low was a cold 50 degrees. In 1971, highs and lows were nearly the same on the 25th (81/62) and 26th (82/61). In 1970 the high was a cool 64 with a low of 54, a cool day. In 1969 the high was 96 with a low of 75, a hot day. In 1963 the high was 92 with a low of 62, a 30 degree spread. In 1959, highs and lows were nearly the same on the 25th (91/70) and 26th (90/71).

More recently, the spreads were all large: 35 degrees in 1979 (88/53), 34 degrees in 1986 (90/56) and 32 degrees in 1984 (88/56).

On the cool side, in 1982 the high was 69 with a low of 52. A decade later, in 1992, the high was 73 with the record low of 50. The low was also 50 in 1974. The record coolest high of 60 occurred way back in 1884, at a time when the official readings were taken adjacent to Lake Michigan. 27 of the last 33 lows (82%) were in the: 50s (11) and 60s (16). Six lows were in the warm 70s. 1970 was O'Hare's coolest June 26th as the high was 64 (O'Hare's coolest high of the date) with a low of 54.

There was an instance of back-to-back years in which temperatures were just about as opposite as they can be. In 1982 the high was 69 with a low of 52,  overall 11.5 degrees BELOW normal. Then in 1983 the high was 99 with a low of 72, overall 13.5 degrees ABOVE normal.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:44 and sunrise is at 5:19. Sunset is at 20:34 and twilight ends at 21:08. There's a total of 15 hours, 15 minutes of daylight today and 16 hours, 24 minutes between twilights. We lost a minute of daylight from yesterday. Tomorrow twilight begins at 4:44 and sunrise is at 5:19. The moon reaches first quarter tonight at 22:30. Illumination was 40% at midnight, will be 46% at noon and 51% at midnight tonight. Moonrise is at 12:43 this afternoon. Moonset is at 0:23 tomorrow morning. Moonrise is at 13:52 tomorrow afternoon. Moonlight time is 11 hours, 17 minutes which is an hour and 2 minutes shorter 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. Independence Day is in eight days.