May 10: ORD

Today is May 10th. It's the 130th day of the year. 235 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 68 and the normal low is 45. I've calculated the 32-year averages at 71 and 47.

On the warm side, in 1979 the high was 90 degrees with a low of 67. The record high of 89 occurred way back in 1896. Keep in mind, O'Hare was not the official station of record for Chicago in 1979. This is why that high of 90 is not considered the record. In 1979 Midway was the official station of record and the high was 86 there. In 1987 the high was 88 with a low of 61. That high of 88 fell a degree short of tying the record high. In 1993 the high was 87 with a low of 62. In 2005 the high was 82 with a low of 60. A year earlier, in 2004, the high was 84 with a low of 56. In 2007 the temperatures repeated, as the high was 84 with a low of 56. In 1982 the high was 86 with a low of 53, a 33 degree spread. In 2001 the high was 81 with a low of 58. Other 80s highs were 83 in 1992 and 82 in 1985. The record warmest low of 69 was set way back in 1896, part of that scorching record-high day. 27 of the last 32 highs (84%) were in the: 60s (10), 70s (8) and 80s (9). On the warmer side, one high was in the 90s. On the cool side, four highs were in the: 30s (1) and 50s (3). There have been no highs in the 40s.

In looking back through the years to the first May at O'Hare in 1959, the following instances were notable: In 1978 the high was 72 with a low of 41, a 31 degree spread. In 1977 the high was 62 with a cold low of 31, a 31 degree spread. In 1975 the high was 75 with a low of 45, a 30 degree spread. In 1972 the high was 67 with a low of 35, a 32 degree spread. In 1971 the high was 73 with a low of 42, a 31 degree spread. In 1970 the high was 77 with a warm low of 58, a warm day. In 1969 the high was a cool 53 degrees. In 1966 the high was 52 with a low of 24, a cold day. In 1963 the high was a cool 56 degrees. In 1962 the high was a cool 52 degrees. In 1960 the high was a cold 39 with a low of 37, a small two degree spread and cold day. That high of 39 ties the record coldest high, but unofficially. In 1959 the high was 82 with a low of 61, a warm day.

More recently, we had a small spread of five degrees in 1995 (54/49). The large spreads were: 42 degrees in 1983 (70/28), 37 degrees in 1992 (83/46), 32 degrees in 1999 (74/42), 31 degrees in 1984 (68/37) and 30 degrees in 1985 (82/52).

On the cool side, in 1981 the high was the record coldest high of 39 with a low of 35, a four degree spread. In 1990 the high was 50 with a low of 36. Another cold low was the record low of 28 in 1983. The other 30s lows were 37 in 1984, 38 last year, 39 in 1989 and 39 in 1996. The only other 50s high was 54 in 1995. 1983 was also the year of our biggest spread (see previous section). 20 of the last 31 lows were: 40s (12) and 50s (8). Seven lows were in the colder: 20s (1) and 30s (6). Four lows were in the warmer 60s.

Today is not a major day in Chicago's snow history. Stay tuned, for in one day we had what was our last snow event for the Spring. However, Tom Skilling answered a question from someone who's mother remembered snow on a Mother's Day. Skilling said that back in 1954 Midway recorded a trace of snow on a chilly, rainy day. The low that day was 36 but some suburban areas were near freezing. Skilling pointed out that two years later, in 1956, the high was 89 and this was the warmest Mother's Day. Keep in mind that the first Mother's Day was in 1914.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight is at 5:06 and sunrise is at 5:38. Sunset is at 20:02 and twilight ends at 20:34. There's a total of 14 hours, 24 minutes of daylight today and 15 hours, 28 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 5:05 and sunrise is at 5:37. The moon reaches first quarter today at 15:33. Illumination was 43% at midnight, will be 49% at noon and 55% at midnight tonight. Moonset is at 1:25 this morning. Moonrise is at 12:15 this afternoon. Moonset is at 1:55 tomorrow morning. Moonlight time is 13 hours, 10 minutes which is 36 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 11 days. -Bernie-