May 5: ORD

Today is May 5th. It's the 125th day of the year. 240 days remain. It's week 18 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 66 and the normal low is 44. I've calculated the 32-year averages at 69 and 47.

On the warm side, in 1982 the high was 88 with a low of 61. In 2000 the high was 84 (our most recent 80s high) with a warmest (but not the record) (and most recent 60s) low of 64. Two decades earlier, in 1980, the high was 88 with a low of 52, a 36 degree spread. In 1999 we had our only upper 70s high of 78 with a low of 61. In 1986 the high was 80 with a low of 58. Other warm lows were 57 in 1985 and 56 last year (in 2010). The record high of 94 was set in 1949 and the record warmest low of 70 was set a decade later in 1959. 24 of the last 32 highs (75%) were in the: 60s (14) and 70s (10). On the warmer side, four highs were in the 80s. Four highs were in the cold 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 a cold 43 with a low of 37, a six degree spread, year of the record coldest high and a cold day. In 1977 the high was 79 with a low of 59, a warm day. In 1976 the high was a warm 78 with a low of 42, a 36 degree spread. In 1969 the high was 77 with a warm low of 60, a warm day. In 1968 the high was a cold 53 with a low of 34, a cold day. In 1967 the high was 52 with a low of 32, a cold day. In 1966 the high was a warm 83 with a low of 55, a warm day. In 1965 the high was 77 with a low of 47, a 30 degree spread. In 1964 the high was 83 with a low of 64, a warm day. In 1962 the high was 83 with a low of 60, a warm day. In 1960 the high was 77 with a warm low of 61, a warm day. In 1959 the high was 92 with a low of 70, a hot day. And although 1959 was NOT the year of the record high (94 in 1949), it was the year of the record warmest low (70 at Midway).

More recently, we had large spreads of 32 degrees in 1995 (72/40), 32 degrees in 2005 (70/38) and 30 degrees in 1988 (70/40).

On the cool side, in 1992 we had our coolest high of 52 with the record low of 32. Three years earlier, in 1989, the high was 59 with a low of 37. The other 50s highs were 57 in 1996 and 58 in 2006. The record coldest high of 43 occurred at Midway in 1978. 22 of the last 32 lows (69%) were in the: 40s (12) and 50s (10). Seven lows (22%) were in the cold 30s. Our most recent 30s lows were 38 degrees in the back-to-back years of 2004 and 2005. Three lows (9%) were in the warmer 60s.

The following astronomical data is provided by the United States Naval Observatory. In Crystal Lake, twilight is at 5:13 and sunrise is at 5:44. Sunset is at 19:57 and twilight ends at 20:28. There's a total of 14 hours, 13 minutes of daylight today and 15 hours, 15 minutes between twilights. We gained two minutes of daylight from yesterday. Tomorrow twilight begins at 5:12 and sunrise is at 5:43. The moon is waxing crescent, having passed new two days ago at 1:51. Illumination was 4% at midnight, will be 6% at noon and 8% at midnight tonight. Moonrise is at 7:02 this morning. Moonset is at 22:38 tonight. Moonrise is at 7:54 tomorrow morning. Moonlight time is 15 hours, 36 minutes which is 11 minutes longer 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. Mother's Day is in three days. -Bernie-