If I understand correctly, most solar panels operating optimally around 77F,25C. They decrease in efficiency at higher temperatures. "For every degree Celsius above 25°C, a solar panel’s efficiency typically drops by about 0.3% to 0.5%, depending on the specific panel." So, when it gets around 38C that's maybe 6% less efficient. Not a huge decrease, but something to consider when building your desert solar farm.
https://www.solar-secure.com.au/blog/balancing-heat-and-effi...