This is from a Mazda tech bulletin:

"Ideally, the engine coolant temperature gauge needle should reach the middle of the normal operating range before shutting off the engine."

What does that mean, about 10 o'clock? Please excuse my stupidity.

 

Yes, about the 10 o'clock position. This takes about 5 minutes of driving in my car.

 

could take longer depending on climate

 

Depends on what Mazda considers the NORMAL OPERATING RANGE. If it is from zero to just near halfway point, where the needle ususally parks with the engine is fully warmed up, then the MIDDLE OF THE NORMAL OPERATING RANGE would be a point halfway between those two points. However, if in the Mazda jargon the NORMAL OPERATING RANGE is zero to somewhere just short of the top reading on the gauge (which would presumable indicate overheating), then around the MIDDLE would be the middle of the gauge.

In any case, for what it's worth, I let the needle on my temp gauge reach the point where it usually parks with a fully warmed engine before stressing the engine. I think the sensor associated with this gauge is measuring the water temperature, which would not necessarily be an indication that the engine oil is at the best operating temperature for lubricating the engine components and for the oil injection nozzles.