It happens quite often in Colorado. The cooler temperatures, higher elevations with less atmospheric diffusion and clear skies are big factors. My controller summarizes the day's output/input with one item being Peak Watts. It is not unusual to see a peak of over 400 watts on a system rated at 370 watts. I don't have the ability to see a graphical presentation of the day's production, so I have no idea of the duration or timing of the peak events, but they do occur. I usually tilt my panels to an "optimum" angle. The panels are now 12 years old.
Two of the standard testing conditions for solar panels are sea level at 25C (77F). Both of these conditions are easily exceeded in Colorado. At 10,000 feet, you are above more than 25 percent of the atmosphere. 7800 feet elevation in Arizona will give you about the same result.