June 4: ORD

Today is June 4th. It's the 155th day of the year. 210 days remain. It's week 23 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 76 and the normal low is 53. I've calculated the 32-year averages at 72 and 51.

On the warm side, in 1979 the high was 87 with a low of 63. The only other 60s low was 60 in 1992. In 2005 the high was 86 with a low of 57. The record high of 97 was set in 1977. The record warmest low of 75 occurred back in 1925. 24 of the past 32 highs (75%) were in the: 60s (9) and 70s (15). Six highs were in the warmer 80s. Two highs were in the cool 50s.

Yesterday's high of 87 and low of 55 produced a mean of 71 which is the second warmest June 3rd of the past 33 years and the fourth warmest June 3rd in O'Hare's history (since 1959). The warmest was in 1972 (92 & 64, mean of 78). The second warmest was in 1963 (88 & 60, mean of 74). The third warmest (and warmest of the past 33 years) was in 1981 (81 and 62, mean of 71.5). Today will be another warm day. I'll see where it ranks tomorrow.

In looking back through the years to the first June at O'Hare in 1959, the following instances were notable: In 1978 the high was 80 with a low of 46, a 34 degree spread. In 1977 the high was a hot 96 with a low of 58, a 38 degree spread, overall hot day and day of the record high of 97 at Midway. In 1973 the low was a warm 65 degrees. In 1971 the high was a hot 90 with a low of 60, a 30 degree spread and hot day. In 1968 the high was 83 with a low of 48, a 35 degree spread. In 1967 the high was 80 with a low of 50, a 30 degree spread. In 1961 the high was 82 with a low of 48, a 34 degree spread.

More recently, there were large spreads of 37 degrees in 1994 (80/43), 34 degrees in 1984 (84/50) and 34 degrees in 1988 (79/45).

On the cool side, in 1993 the high was 53 with a low of 44. In 2001 the high was 55 with a low of 46. In 1982 the high was 61 with a low of 43. In 1990 the high was 61 with a low of 44. Other cool highs were 61 in 2000 and 62 in 1996. The record low of 35 was set in 1945. The record coolest high of 47 occurred way back in 1891. 30 of the last 32 lows (94%) were in the: 40s (13) and 50s (17). Two lows were in the warmer 60s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight begins at 4:44 and sunrise is at 5:18. Sunset is at 20:25 and twilight ends at 20:59. There's a total of 15 hours, 7 minutes of daylight today and 16 hours, 15 minutes between twilights. We gained a minute of daylight from yesterday. Tomorrow twilight begins at 4:44 and sunrise is at 5:18. The moon is waxing crescent. Illumination was 6% at midnight, will be 9% at noon and 12% at midnight tonight. Moonrise is at 7:50 this morning. Moonset is at 22:52 tonight. Moonrise is at 8:58 tomorrow morning. Moonlight time is 15 hours, 2 minutes which is 23 minutes shorter than yesterday.

Summer begins today 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. Flag Day is in ten days.