May 9: ORD

Today is May 9th. It's the 129th day of the year. 236 days remain. It's week 19 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 67 and the normal low is 45. I've calculated the 32-year averages at 71 and 48.

On the warm side, in 1979 the high was a near-record 89 degrees with a low of 69. In 1993 the high was 87 with a low of 60. In 1987 the high was 85 with a low of 55, a 30 degree spread. In 2004 the high was 88 with a low of 52, a 36 degree spread. A year later, in 2005, the high was 77 with a low of 62. Two years prior, in 2003, the high was 84 with a low of 54, a 30 degree spread. In 2007 the high was 77 with a low of 61. Other 80s highs were 81 in 1985 and 80 in 2001. The record high of 94 and record warmest low of 69 were set on the same hot day back in 1934. Although O'Hare had a low of 69 in 1979, at the time O'Hare was not the official station of record for Chicago. Midway had a low of 67 in 1979. Furthermore, O'Hare's low was also 67 in 1965. 20 of the last 32 highs (62%) were in the: 60s (8) and 70s (12). On the warmer side, seven highs (22%) were in the 80s. On the cool side, five highs (16%) were in the 50s.

In looking back through the years to the first May at O'Hare in 1959, the following instances were notable: In 1977 the high was 51 with a low of 32, a cold day. In 1974 the high was a cold 49 with a low of 37, a cold day. In 1970 the high was 78 with a warm low of 61, a warm day. In 1966 the high was 44 with a low of 27, a cold day. 1966 was also the year of the record coldest high (42 at Midway). In 1965 the high was 82 with a low of 67, a warm day. In 1963 the high was a hot 86 with a low of 55, a 31 degree spread and warm day. In 1962 the high was a cool 52 degrees. In 1960 the high was a cold 41 with a low of 36, a five degree spread. That high of 41 was actually colder than the record coldest high, but keep in mind, O'Hare was not the official station of record for Chicago in 1960.

More recently, we had large spreads of 34 degrees in 1981 (72/38) and 30 degrees in 1982 (76/46).

On the cool side, in 1983 the high was 55 with the record low of 27. Last year, in 2010, the high was 58 with a low of 38. The other 30s lows were 35 in 1980, 37 in 1984 and 38 in 1981. The record coldest high of 42 was set in 1966. 23 of the last 32 lows (72%) were in the: 40s (12) and 50s (11). Five lows were in the cold: 20s (1) and 30s (4). Four lows were in the warmer 60s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight is at 5:08 and sunrise is at 5:39. Sunset is at 20:01 and twilight ends at 20:33. There's a total of 14 hours, 22 minutes of daylight today and 15 hours, 25 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 5:06 and sunrise is at 5:38. The moon is waxing crescent and will reach first quarter tomorrow at 15:33. Illumination was 33% at midnight, will be 38% at noon and 43% at midnight tonight. Moonset is at 0:51 this morning. Moonrise is at 11:05 this morning. Moonset is at 1:25 tomorrow morning. Moonlight time is 13 hours, 46 minutes which is 28 minutes shorter than yesterday.

The warm part of Spring (Warm Spring) began on April 13. Warm Spring runs for 52 days, through June 3. High temperatures in this period are usually in the 50s, 60s and 70s. Warmer 80s and 90s occur infrequently. Armed Forces Day is in 12 days. -Bernie-