Like the other guy said, just the oil viscosity ratings for cold and warm temperatures.

What this means for practical purposes is that for modern engines, in general a dino based 5W30 oil is good for below freezing to maybe 100 degrees, a little thin for my taste above 100. A 20W50 would be good for maybe 40 degrees to well over 100, turns to fudge below freezing. The range varies a lot depending on engine condition and how you drive it. An old loose engine will want heavier oil. Towing in hot conditions would be safer with heavy oil. If you live in Alaska and it is winter, you might want to go with a 0W30 oil.

Synthetic flows a lot easier and the viscosity almost doesn't matter. A 5W30 syn should be good for almost anything you can throw at it. The 0W30 and 20W50 syn are more marketing in my opinion. I run a 5W30 syn in all my vehicles. This includes high performance, towing in extreme heat and cold, etc. No complaints in almost 25 years.

Dino is excellent too, but you need to be more selective in viscosity choice.

Don't know if the following argument is still valid since dino oils are much better now, but 5 or more years back there was a big problem with the wide spread range of viscosity. Anything wider than about 20 points was considered risky. For example 10W40 was very popular, but the 30 point spread meant it had a lot of viscosity index improvers, essentially plastic. Plastic is a poor lubricant. The 10W40 oils were causing problems in stressed engines where essentially the oil oxidized and sludged things up,it was called the black death, not good. Some auto manufacturers voided warranties if you used 10W40. Interestingly, 20W50 did not have the problem since it startred with a heavier base oil(20W), so it did not oxidize like the 10W base oils did. None of this applies to dino and perhaps with new technology that is moot. Still there are enough choices that I would just avoid 10W40 anyway.

Just my opinion and I am only a user, not an expert on oil.

Jim Henderson