Checking Oil Level

Pulling the dipstick might smear it downward, but enough oil should remain to show a line where the top surface originally was.

Capillary action is a different thing. It's related to surface tension and can cause a liquid climb slightly against a surface, it is particularly noticeable in a narrow tube.

 

The capillary action will be more prominent with the thinner oil. The coating of oil sticking to the dipstick will also be thinner making it harder to read. This is the only downside I have found to using 0w/20 oil over the last 100,000 miles.

John (Britprius)

 

The oil level in my Prius does not change measurably on the dipstick between 10,000 mile oil changes.
It is possible that higher temperatures could have an effect on the amount of oil used, but I am not entirely convinced that climate has much to do with oil use.
The engine temperature particularly the cylinder walls is governed by the water temperature in the engine more than outside air temp. The water temperature is governed by the engine thermostat.
The oil amount sticking to a cylinder wall would be tiny and almost instantly be bought up or down to the temperature of the cylinder.
If oil use is external temperature controlled the simple answer would be to fit a lower temp thermostat and an oil cooler. Thus lowering the temperature of the engine and the oil.

John (Britprius)

 

Not if he has a long drive. Operational oil temperature does vary with a little bit with outside (ambient) temperature, but also with driving style and terrain (eg spirited driving over mountains can substantially increase oil temperature). The effect of outside air temperature on maximum oil temperature is not particularly large. There are too many other factors to put this down to just climate.