Record readings usher in summer season

2008's first triple-digit temperature was late in getting here, but making up for it is the heat's intensity.

Summer informally arrived at 12:39 p.m. Sunday, when the Valley's official thermometer reached 100 degrees. More than three hours later, the temperature maxed out at 105 - 11 degrees above normal but two degrees shy of the day's record.

Temperatures topped the 100-degree mark throughout the Sun Cities area. Leading the way was Sun City West, which recorded a 103-degree high. Sun City Grand and Sun City came in at 102 and 100, respectively.

And the National Weather Service expects this belated heat wave to strengthen. The forecast highs for today and Tuesday are 108 and 109, respectively, which would break the previous daily records by three degrees.

In preparation, the Weather Service has issued an excessive heat warning for today and a watch for Tuesday. The latter will likely be upgraded to a warning, the forecasters acknowledged.

According to the agency's climate records for Phoenix, which go back to 1985, the first 100-degree reading was five days later than usual. When considering only the last 30 years, to account for the Valley's urban sprawl, on average the first 100-degree day was May 1.

In fact, this is the latest debut of 100 degrees since 1999, and the fourth-latest in the last 25 years.

What's to explain why the heat came so late?

"Normal climatological cycles," Weather Service meteorologist Mike Bruce said Sunday afternoon.

In other words, this is nothing but the vagaries of weather.

As Bruce noted, the temperature reached 99 on April 29. No, 99 degrees is not 100, but looking deeply at the difference "is trying to split hairs," he said.

If Phoenix's historic average holds up, with three straight days of triple-digit highs this would mean Valley residents will endure just another 107 days of 100-degree temperatures this year.

But in the short term, relief is on the way.

A powerful storm system is forecast to dive across the West, and predictions call for it to drastically turn down the heat and turn up the wind.

"Being May, the chances of any widespread precipitation are still pretty slim," Bruce said. "But we could see isolated storms in the mountains, as we saw this past week."

Beating the heat
The National Weather Service offers the following heat-related safety tips:
• Slow down. Strenuous activities should be reduced, eliminated or rescheduled to the coolest time of the day.
• Dress for summer. Lightweight light-colored clothing reflects heat and sunlight, and helps your body maintain normal temperatures.
• Put less fuel on your inner fires. Protein-heavy foods increase metabolic heat production and water loss.
• Drink plenty of water or other nonalcoholic fluids, even if you don’t feel thirsty.
• Spend time in air-conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat.
• Don’t get too much sun. Sunburn makes the job of heat dissipation that much more difficult.