Diesels better in wet weather, really? I've never owned one, but neither have I ever had to leave my petrol car at home because it was raining, and I've owned some fairly old cars :)
Not to be antagonistic but what gasoline engines which are not a hybrid get (US or Imperial) 50 to 60mpg? I could see diesel engine vehicle average mileage for small manual transmission getting high Imperial 60mpg gas maybe high 40s mpg.
Deep water and gasoline engine don't tend to work well, and in my region snow gets under the hood then melts (can't get it all out) which causes problems.
Compared to a gas engine a diesel engine will run underwater if it has air you see 4x4 trucks with snorkels on the A-pillar (and some other sealing) in Africa countries, Australia and military use too.
* I get about 1.25x the mpg in the diesel to her in the petrol. 1.5x compared to myself in the petrol (no mpg quotes because it depends on the type of driving)
* The torque is useful. I drive a 30 minute commute, mainly motorway. If I drive hers it is a noticably worse drive.
* For in town driving hers feels better every time. Easier to handle with no load (hauling something? Use the diesel), the diesel tricks me into speeding.
* Wet weather? Never had weather problems in either car.
So whilst I am definitely a less efficient driver than her I save a significant amount on fuel by having a diesel, and my calculation shows its several hundred a year better than if I had bought the petrol when I had the chance - more than covering the increased cost of the initial purchase.
Better in wet weather how? I've to assume that you must mean something related to torque and traction, as the only problem one might have with a gasoline engine in the wet might be ignition parts. Though never much of a problem on maintained vehicles, what little problem there was went away when distributor caps and wires went away twenty years ago.
But also diesel engines have so much more torque you don't have to wring the piss out of the engine to get moving. With diesel you get most torque at 1500 rpm but for a gasoline engine you're revving it to 5000 rpm to get any torque, and burning more fuel.
Less rpm less engine wear too but most diesel engines are built very well to handle the compression ignition.
Diesel are also better in wet weather compared to gasoline engines although gas engines are better than the used to be.
I think people in the US still imagine a diesel with visible exhaust spewing out soot something from 30 years ago.