Anything using electrolytic capacitors will have an increased failure rate in a desert environment due to heat.

A rapid (and unexpected) increase in equipment failures could be the direct result of not providing enough temperature protection for the devices (such as enclosure cooling, sun shades, etc). Temperatures in an enclosure can climb much higher than ambient due to the sun heating the enclosure, and if this is not taken into account you can find your internal ambient enclosure temperature exceeding the maximum rating of the device.