Forecast of the Day • A National Weather Forecasting Contest

Well Lufkin was foggy/misty/overcast until 1 pm. It finally started clearing and the temperature increased, but the slow start meant that they reached only 87 F, lower than any of the model statistical forecasts.

Of course the desert is often cloud-free, leading to the maximum possible amount of solar radiation. But probably the most important thing is that the lack of rainfall means that the soil stays very dry for long periods in the desert. Given an equal amount of solar radiation between a site with a wet climate and lots of vegetation (e.g. Florida) and a dry desert site, the wet site will warm up less, because some of the energy is used to evaporate water from the soil and drive transpiration from the vegetation, rather than increasing the air temperature.