I have just seen the cute little blue snow flake for the first time (apologies if this is old news for those in the North )

And the cold weather seems to be making its mark on fuel consumption - I used to get nearer 62mpg on a trip to Swansea

This is a view of summer vs winter in the Audi (yes, I am sad).

Edited 4 November, 201312 yr by Juniperz

You need a timeline for reference along the bottom.

You are quite right, but this was 103 tanks full, so the dates would run over each other.  Suffice to say that the red peaks were summer and the red troughs were winter!  

Not sure why the peaks this summer were less extreme - maybe I was thrashing it in advance of a new car coming??

The blue values are a rolling average of the last 10 tanks BTW ("R10").

The green line does show how the economy improves over time.  About 60 000 miles and 4 years to the week.

Do you by any chance drive mostly short journeys? The biggest obvious affect on mpg between winter and summer driving is that during the winter an engine will take longer to reach optimum operating temperature. The time difference probably only takes a minute or so.

 

Cool air actually helps engine efficiency, air-conditioning is used less and there is generally less traffic on the roads during winter months, so this can (for some people) increase mpg. At the end of the day it depends how and where you drive. For instance, people are more inclined to go on long fuel economic journeys during the summer, whilst during the winter you might drive around the corner, or take the kids to school in the car because it is raining. All I am saying is that cold weather by itself does not necessarily decrease mpg.

 

I think it is habit changes rather than weather which cause such swings.

Edited 4 November, 201312 yr by Orville

No, that is mostly motorway driving (Bristol - Swansea return once or twice a week).  If it's local, I walk or cycle - and make the kids do likewise!.

I was on the motorway with 5 mins of leaving home at 6am today, but I believe that the whole journey was less economical than it had been when it was warmer.  And it wasn't particularly windy or at all wet today, so those aren't factors.  Wet roads used to affect the Audi very badly - I blamed the 245 wide tyres.

Great data Juniperz - first time I've seen proper results showing the improvement with age and seasonal changes. I've never had the discipline to keep it up for that long, so to speak.

I have just seen the cute little blue snow flake for the first time (apologies if this is old news for those in the North

And those council gritters have been out - salt all over my lovely new car !!!!!!!!!

Great data Juniperz - first time I've seen proper results showing the improvement with age and seasonal changes. I've never had the discipline to keep it up for that long, so to speak.

Thanks - and to show that my sadness knows no bounds, I could do the same for 16 months in a Volvo V50 2.0D, 4 years in a Honda Accord Estate 2.2D, 4 years in a Passat Estate 1.9D.  The last one could be tricky - it was in Lotus 1-2-3!!!

First really cold morning for me and the Bravo was showing under 50mpg today.

In the summer on a good day it will be over 60mpg on my commute in.
Time to block up the grille.

I have just seen the cute little blue snow flake for the first time (apologies if this is old news for those in the North )

 

 

I'd question the accuracy of your temperature.

 

You're in Bristol?

 

I was in Bristol this morning at 6.20a.m driving to a gym (work commitments take me away from my beloved frost-free Cornwall from time to time!) and the temperature outside was 5.5C.

 

I'd be surprised if it dropped 2 degrees in an hour, particularly as it was dark at 6.20 and light at 7.20?

I left Bristol at 6am-ish and didn't think too much about the temperature.  At about 7:10 I came up to the 50mph zone by Port Talbot and the car chimed and the snowflake appeared with a message too - 4 degrees shown.  I saw as much as 5 degrees with the snowflake later and as you can see, when I parked up (near J46), it was 3.5 degrees.  (I almost, but not quite, said I had driven Bristol - Swansea in the first post).

I drove for about an hour and a half on the A55 at a steady 70 yesterday - low 50's compared to high 50'susually. I have recorded each fill on fully thus far so will be able to plot a similar run chart. Don't think they are valid until about 20 fills but will make for a good real life test over the next 4 years!

... I believe that the whole journey was less economical than it had been when it was warmer.  And it wasn't particularly windy or at all wet today, so those aren't factors.  Wet roads used to affect the Audi very badly - I blamed the 245 wide tyres.

Did the same journey this morning, at about the same time.

Monday: Temperature 3.5-5.5 degrees, dry road, 55mpg

Wednesday: Temperature c9.5 degrees, wet road all the way, 61mpg

So I definitely think that low temperature kills economy.  That's another reason why I prefer summer to winter.