Marathon running is a sport that tests the endurance and physical limits of those participating, with few things playing a larger factor than the weather.
Fortunately for those running in the Dick's Sporting Goods Pittsburgh Marathon, the forecast for Sunday's race is a favorable one.
The expected high Sunday is 70 degrees with a low of 52 degrees, all under partly cloudy skies.
The temperatures are not expected to be in the range of what many would consider to be dangerous for the runners.
Sunday's temperatures should not differ significantly from the conditions at the beginning of the 2012 Pittsburgh Marathon.
However, by 11:30 a.m., the temperatures reached the high 70s, which prompted race officials to raise the red flag that warns of possible heat-related health risks.
Race organizers said Wednesday that they will closely monitor six special thermometers along the marathon's course.
The thermometers measure ambient heat, radiant heat and humidity, all of which provide a more accurate measure of the heat that the race participants have to endure.
For runners and walkers in the full and half marathons, the race is set to begin at 7 a.m.weather
Craig Meyer: email@example.com and Twitter @CraigMeyerPG.