[Ashm3_uk]

I drive a Alfa 159 as my daily driver. My M3 E93 is my occasional toy along with my Ducati 899.

When topping up fuel I use an app which allows me to fill up pay on my phone without having to go in to the shop.

The app allows me to make a note of the mileage every time I fill up.

I've noticed in the summer I constantly get 60miles extra per fill up on the Alfa 159 (diesel). And about 30miles extra per fill up on the BMW.

I use the same fuel every time. Always fill the tank. Always reset the speedo as soon as I fill up.

Driving habits are the same all year round. Same routes etc.

Thoughts?