July 13: ORD

Today is July 13th. It's the 194th day of the year. 171 days remain. It's week 28 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 63. I've calculated the 32-year averages at 84 and 64.

On the hot side, in 1995 the high was the record high of 104 with the record warmest low of 81. Two years later, in 1997, the high was 94 with a low of 72. The high was also 94 in 1988. The warmest 70s lows were 74 in 1981 and 73 in 2005. 24 of the past 32 highs (75%) were in the: 70s (9) and 80s (15). Seven highs (22%) were in the hot: 90s (6) and 100s (1). One high (3%) was in the cool 60s.

In looking back through the years to the first July at O'Hare in 1959, the following instances were notable: In 1976 the high was 86 with a low of 53, a 33 degree spread. In 1974 the high was a hot 95 with a low of 69, hot but not a hot day compared to normal. In 1973 the high was a hot 95 with a low of 72, hot but not a hot day compared to normal. In 1967 the high was a cool 67 with a low of 52, a cool day. That low of 52 was equal to the record low. In 1964 the high was 71 with a low of 49, a cool day. That low of 49 was colder than the record low.

More recently, there was a large spread of 33 degrees in 1983 (89/56).

On the cool side, in 1990 the high was 66 with a low of 59, a seven degree spread. Three years earlier, in 1987, the high was 74 with a low of 54. The record low of 52 was set in 1975 at Midway. Another cool high was 72 in 1994. The record coolest high of 64 occurred back in 1926. 17 of the last 32 lows (53%) were in the 60s. Nine lows (28%) were in the cool 50s. Six lows (19%) were in the warm: 70s (5) and 80s (1).

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:55 and sunrise is at 5:29. Sunset is at 20:29 and twilight ends at 21:03. There's a total of 15 hours of daylight today and 16 hours, 8 minutes between twilights. We lost two minutes of daylight from yesterday. Tomorrow twilight begins at 4:56 and sunrise is at 5:29. The moon is waxing gibbous and will be full as the full Buck or Thunder moon in two days at 1:40. Illumination was 95% at midnight, will be 97% at noon and 99% at midnight tonight. Moonset is at 3:44 this morning. Moonrise is at 19:19 tonight. Moonset is at 4:49 tomorrow morning. Moonlight time is 8 hours, 25 minutes which is eight minutes longer 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 11 days.