How hot was it today, really?

This afternoon, the temperature here in Houston topped out at 109 degrees Fahrenheit, according to the weather app on my iPhone. Although there's no question that today was a brutally hot day, that number seemed sort of peculiar to me: was it really that hot for a day in June? And if so, had it ever been 109 degrees in Houston in June before? Fortunately, Chronicle science blogger Eric Berger already had an answer:

Is it really that warm? For Houston, that would be remarkable. Fortunately my iPhone, and your iPhone, is wrong.

A temperature of 108 degrees today would be historic, considering the warmest June day ever recorded in Houston is 105 degrees (it happened twice, last June). It would also be one degree below the warmest temperature ever recorded in Houston.

Fact is, through 1 p.m., today’s high temperature is 102 degrees as measured at the official Bush Intercontinental Airport station.

So why is the iPhone so much higher?

It’s a question Dwight Silverman and I dug into last August, and the answer is that the default iPhone weather data point for “Houston” is the Houston/Hermann Medical Center weather location. It’s the the helipad at Memorial-Hermann Hospital in the Texas Medical Center, some 200 feet above the ground.

Berger says that "it makes no sense" for a weather station to be located there, as the temperature reading would clearly be affected by heat being radiated from the surrounding pavement and buildings as well as, perhaps, the exhaust from the Life-Flight helicopters that land there. In that regard, the Memorial-Hermann helipad temperature reading is probably about as accurate as the temperature display in your car, which registers engine heat and re-radiated pavement heat as well as the actual air temperature.

Perhaps the person who decided to put Houston's default weather data point at that location wanted a location that was as close to the city center as possible. Who knows? At any rate, today's official high was 105 degrees today, as recorded at Bush Intercontinental Airport.

Of course, I could also ask if it makes sense for the city's "official" weather data point to be located at an airport twenty miles from the city's center.

I could also ask if the difference between 105° and 109° is really that meaningful. Today was miserably hot, regardless of the actual number.