Half the year is over. Now that July is just about here, it’s time to look ahead at what the month brings climatologically to southwestern Connecticut. Not surprisingly, July is the warmest month of the year with a mean temperature of 74 degrees. The hottest temperature ever recorded at Sikorsky Memorial Airport happened July 22, 2011, when the mercury topped 103 degrees, tying the record originally set in 1957. The following day, July 23, 2011, another record high of 96 degrees was recorded.
The mercury reached the century mark two other times — July 2, 1966 and July 5, 1999. In fact, the average daily temperature climbs from 72 degrees at the start of the month to 75 by July 31. The warmest July on record happened 18 years ago, in 1994, with an average temperature of 78.4 degrees. However, last July was one of the warmest on record with an average temperature of 77.6 degrees.
July of 2010 was another hot one. You may recall the heat wave over the Independence Day holiday weekend. The high temperatures from July 4 through July 7, 2010, were 97, 93, 98, and 95 degrees, respectively. In fact, record high temperatures were established July 6 and 7. The mercury also reached 95 degrees July 24. The average temperature for the month was 78 degrees, just shy of the all-time record.
Many people have asked me why the hottest time of the year happens over a month after the first day of Summer. Well, it takes the Earth awhile to absorb the heat. As the Sun’s angle gets higher in the sky and the days grow longer in May and June, the Northern Hemisphere slowly starts to warm.
It’s much like warming your home. When you turn your thermostat up to 72 degrees after being away all day in the Winter, it will take awhile for the house to warm up. It doesn’t happen instantly. That’s why our hottest days are typically in July and early August.
On the flip side, the coolest temperature ever recorded in these parts in July was 49 degrees on July 1, 1988. Aside from that, every record low for the month is in the 50s. Believe it or not, according to the National Weather Service record book, a trace of snow fell at the airport on July 4, 1950. I find that too hard to believe.
As far as precipitation is concerned, the wettest July on record happened in 1971 when over a foot of rain (12.84″) fell. The average monthly rainfall is 3.77 inches. There have been several memorable rainstorms in July. For example, nearly a half-foot (5.95″) of rain fell on July 19, 1971, and nearly four inches (3.93″) was recorded on July 29, 1990. Two other days delivered well over three inches of rain — July 30, 1960 (3.57″) and July 23, 1953 (3.45″).
The length of daylight actually decreases next month. For example, on July 1, the Sun rises at 5:23 and sets at 8:30. By the middle of the month, on July 15, the Sun rises at 5:32 and sets at 8:24. However, at the end of the month, it rises at 5:47 and sets at 8:10, meaning we lose 44 minutes of daylight. Remember, the “longest” day of the year happened at the Summer Solstice in late June.
Our weather will be warm and humid today with a good chance of showers and thunderstorms, some of which may produce locally heavy rain. High temperatures will climb into the 70s to close to 80 degrees. More of the same is expected tomorrow, although there will be breaks of sunshine, with highs in the upper 70s to close to 80 degrees. The weather pattern will quiet down later this week, though, before it turns hotter for the Independence Day holiday weekend.
Paul