July 26: ORD

Today is July 26th. It's the 207th day of the year. 158 days remain. It's week 30 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.

According to the National Climatic Data Center (NCDC), the normal high is 84 and the normal low is 64. I've calculated the 32-year averages at 83 and 65.

On the hot side, in 1997 the high was 97 (our most recent 90s high) with a low of 73. In 1982 the high was 91 with a low of 73. Our only other 90s high was 90 in 1987. The record high of 99 was set in 1955. The record warmest low of 80 occurred back in 1916. 22 of the past 32 highs (69%) were in the 80s. Three highs (9%) were in the hot 90s. Seven highs (22%) were in the cool: 60s (1) and 70s (6). There have been two significant stretches of sub-90 degree highs. The first was nine years from 1988 to 1996 and the second is still ongoing, 13 years from 1998 to 2010.

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1972 the high was a cool 70 with a low of 63, a seven degree spread. In 1962 the high was 75 with a cold low of 49, a cool day.

More recently, there was a small spread of five degrees in 1981 (71/66).

On the cool side, in 1984 the high was 67 (our only 60s high) with a low of 55. In 1991 the high was 78 with the record low of 53. The record low of 53 was originally set in 1962. Another cool low was 54 in 1994. Another cool high was 71 in 1981. The record coolest high of 66 occurred way back in 1891. 18 of the last 32 lows (56%) were in the 60s. Seven lows (22%) were in the cool 50s. Another seven lows (22%) were in the warm 70s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 5:08 and sunrise is at 5:40. Sunset is at 20:19 and twilight ends at 20:51. There's a total of 14 hours, 39 minutes of daylight today and 15 hours, 43 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 5:09 and sunrise is at 5:41. The moon is waning crescent, having reached last quarter three days ago at 0:02. Illumination was 22% at midnight, will be 18% at noon and 14% at midnight tonight. Moonrise is at 1:31 this morning. Moonset is at 17:04 this afternoon. Moonrise is at 2:21 tomorrow morning. Moonlight time is 15 hours, 33 minutes which is 13 minutes longer than yesterday. Moonlight time is two minutes short of peaking.

Summer began June 4 and runs for 110 days through September 21. High temperatures in this period are usually in the 70s and 80s. Highs in the 60s, 90s and 100s occur infrequently. Labor Day is in 41 days.