July 5: ORD

Today is July 5th. It's the 186th day of the year. 179 days remain. It's week 27 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 83 and the normal low is 62. I've calculated the 32-year averages at 84 and 62.

On the hot side, in 1999 the high was 94 with a low of 79. Five years prior, in 1994, the high was 95 with a low of 77. Last year, in 2010, the high was 91 with a low of 78. The other 90s highs were 98 in 1988, 95 in 1982, 94 in 1980 and 91 in 1986. Another warm low was 74 in 1986. The record high of 102 and record warmest low of 82 were set on the same very hot day back in 1911. 24 of the past 32 highs (75%) were in the: 70s (9) and 80s (15). Seven highs were in the hot 90s. One high was in the cool 60s (67 in 1983).

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1977 the high was 94 with a warm low of 77, a hot day. In 1972 the high was 73 with a cold low of 44 (a low cooler than the record low which was set this day at 46 degrees), a cool day. In 1967 the high was 66 (year of the record coolest high of 65) with a low of 48, a cool day. In 1965 the high was 79 with a cold low of 42 (a low cooler than the record low), a 37 degree spread and overall cool day. In 1964 the high was 83 with a cold low of 46 (tied with the record low), a 37 degree spread. In 1963 the high was 85 with a cool low of 50, a 35 degree spread. In 1961 the high was a cool 69 degrees.

More recently, there were large spreads of: 38 degrees in 1988 (98/60), 36 degrees in 1980 (94/58), 35 degrees in 1982 (95/60) and 32 degrees in 1996 (86/54).

On the cool side, in 1983 the high was 67 with a low of 48. Four years earlier, in 1979, the high was 71 with a low of 47. The record low of 46 was set in 1972 at Midway. The record coolest high of 65 occurred in 1967 at Midway. 25 of the last 32 lows (78%) were in the: 50s (10) and 60s (15). Two lows were in the cold 40s and five were in the warm 70s. Note that the two 40s lows (since 1979) occurred in 1979 and 1983. The closest we've come to a low in the 40s was a low of 53 in 1997.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:49 and sunrise is at 5:23. Sunset is at 20:33 and twilight ends at 21:07. There's a total of 15 hours, 10 minutes of daylight today and 16 hours, 18 minutes between twilights. We lost a minute of daylight from yesterday. Tomorrow twilight begins at 4:49 and sunrise is at 5:24. The moon is waxing crescent. Illumination was 18% at midnight, will be 23% at noon and 28% at midnight tonight. Moonrise is at 10:20 this morning. Moonset is at 23:00 tonight. Moonrise is at 11:32 tomorrow morning. Moonlight time is 12 hours, 40 minutes which is 43 minutes shorter than yesterday.

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. Parent's Day is in 19 days.