Poor MPG in rain?

[joesmad4it]

Has anyone experienced poor MPG in the rain or am I going mad? I drove to work yesterday in my Cupra TDI in the dry and averaged 55+ mpg, this morning drove the same (but in rain) and did 10mpg less!!

Is this due to larger wheels to my 16" FS wheels or am I being a complete numpty and my brakes might be binding?

 

[andycupra]

driving in the rain shouldnt make any difference, (anything significant)
on one side you should be booting it less... so could be more efficient.
on the other you will need to slow for corners more and therefore accelerate more if you are making the journey in the same time. (this also suggests you are driving faster between corners..)
Or if there is traffic, you may find that people drive slower, or more erratically in the rain. (slower normally being good for mpg, but not if you are dropping down a gear or 2)

The other option is if the whether is colder, then it may have taken longer for the car to reach operating temp.

How long in the drive? type of road? time taken? traffic? speed typical?

oh and larger wheels wont help if they are heavier.. - i presume the rolling radius has been maintained!?!?

 

[jaz205gti]

i get this problem all the time maybe its the maf
my mpg seems to be around 10mpg less than it used to be
disconnected the maf and my mpg seemed to go up!
although power was down ?

 

[Nath.]

The tyres have to clear the rain through the tread and this extra workload will use a tad more fuel. The wipers and lights being on, rear screen heater along with heating blower and heated mirrors will load the engine a bit more but not 10MPH more.