The temperature exceeded 40 C and the speed limits are high. The truck performed flawlessly, and did not use any oil in 2000 kilometres of driving. I also notice the oil pressure gauge remained in the normal range with the engine idling, instead of dropping to the low end of the scale as it has done during previous hot weather driving. Several cars require synthetic engine oil to meet the manufacturer's warranty requirements. Typically, these are high performance vehicles that generate a lot of heat in the engine during spirited driving.
Synthetic oils provide the extra protection during hot engine conditions.
It was only a few weeks later that I was able to check the oil performance during cold weather. While we have not reached the frigid temperatures of winter, the temperature has already dropped to -14 C where I was driving. I noticed the engine cranked quickly, and the oil pressure rose immediately upon starting the truck. This seemed to be a faster rise in oil pressure during cold temperatures than I previously had with regular oil. The synthetic oil did not seem to thicken as much during cold temperatures and therefore could provide better lubrication during cold weather starting.