Scorcher of a summer

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PHOENIX -- It's been a scorcher of a summer.

While we have not had any record daytime highs, it's the nights that have made the summer of 2010 the ninth hottest on record.

The average overnight low was nearly 83 degrees during June, July and August. According to the National Weather Service, that's about 3 degrees above the average. The kicker, however, was the number of nights the mercury never dropped below 90 degrees. One two nights in July, the 16th and 19th, the low was 94.

Scientists say those hot nights are the results of an urban heat island, where buildings, concrete and asphalt absorb heat during the day and then slowly release it at night when the rest of the desert cools off.