Winter fuel consumption

[briwy]

We had the van out for it's first decent run since fitting the winter tyres this weekend and found the fuel consumption to be around 10% down on normal.
Over a run of about 350 miles the consumption has dropped from 34ish to 30 compared to warmer weather over the same run. This is on a 4Motion 180.
Could be a mixture of higher rolling resistance on the tyres and winter diesel which I understand has a lower cetance rating than normal summer diesel.
Just wondering if anyone else has found this?

 

[beardie]

Number of factors. The engine takes longer to get to normal operating condition, the roads are more likely to be wet (higher rolling resistance). The lights, windscreen wipers etc are more likely to on for longer. I think standard manufacturer fuel consumption figs will be at 21 or 25 deg C