June 27: ORD

Today is June 27th. It's the 178th day of the year. 187 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.

According to the National Climatic Data Center (NCDC), the normal high is 82 and the normal low is 60. I've calculated the 32-year averages at 84 and 62.

On the hot side, in 1998 the high was 95 with a low of 69. In 2005 the high was 95 with a low of 68. In 2007 the high was 91 (our most recent 90s high) with a low of 71. The only other 90s high of the past 32 years was 93 in 1991. The other 70s lows were 70 in 1999 and 72 last year (in 2010). The record high of 101 was set in 1971. The record warmest low of 79 occurred back in 1931. 22 of the past 32 highs (69%) were in the 80s. Four highs (12%) were in the hot 90s. Six highs (19%) were in the cool: 60s (1) and 70s (5). Our most recent 70s high was 77 in 2000. The lone 60s high was 69. It occurred on the coolest day of the past 32 years in 1992. It didn't rain that day, but winds were Northeast, off the lake. The prior year, 1991, saw one of our hottest highs, 93 degrees.

In looking back through the years to the first June at O'Hare in 1959, the following instances were notable: In 1971 the high was a hot 96 with a low of 69, a hot day. 1971 was the year of the record high of 101 at Midway. In 1968 the high was a cool 58 with a low of 55, a three degree spread and cool day. In 1959 the high was 91 with a warm low of 75, a hot day.

The June 1964 heat wave was impressive. The following were the highs and lows: 26th (90/65), 27th (90/61), 28th (91/61), 29th (91/62) and 30th (90/61).

More recently, the spreads were all large: 32 degrees in 1981 (81/49) and 30 degrees in 1996 (89/59).

On the cool side, in 1992 the high was our only 60s high of 69 with the record low of 47. In 1988 the high was 78 with a low of 51. In the prior year, 1987, the high was 75 with a low of 54. The only other 40s low was 49 in 1981. The record coolest high of 57 occurred way back in 1905. 27 of the last 32 lows (84%) were in the: 50s (10) and 60s (17). Our most recent 50s low was 53 in 2004. Two lows were in the cool 40s and three were in the warm 70s.

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 4:45 and sunrise is at 5:19. The moon is waning crescent. Illumination was 17% at midnight, will be 14% at noon and 10% at midnight tonight. Moonrise is at 2:12 this morning. Moonset is at 17:22 this afternoon. Moonrise is at 2:52 tomorrow morning. Moonlight time is 15 hours, 10 minutes which is 28 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. Independence Day is in seven days.