C in the rain...

Raining here too and I clocked in my morning commute at 56mpg. Actually slightly higher than my normal. I attributed it to slower moving traffic, never got up past 55ish on the freeway.

 

Wow that is a significant drop. Is the outside temp much colder today than it has been?

 

Check your tire pressure. Several people on this forum driving the hatchback run with 44psi front, 42 psi rear. That's what I have in my PHV tires.

 

Yes, normal. Pushing water with the tires takes a lot of effort.

 

When I bought my c, it rained for about a month (Oregon). My mileage went up as soon as it stopped raining and the temperature went up. Both of those have an effect. The engine is also breaking in, but I've still only driven it 600 miles, so I'm not sure how much that had to do with it.

 

Ash, glad to hear you mpg went up!


Rain will change mpg, and it all depends on driving characteristics.
Take benj for example. (lower speed=higher mpg)

 

Also, wind. If it's windy, that will affect your mpg more than anything.

 

All the 'spray' you see is lifted from the road surface by energy from the cars. MPG has to go down to get that spray.

 

Tis true indeed! headwinds are my enemy on the freeway.

 

We took a 230 mile (mostly interstate) round trip when we had less than 200 miles on the ODO. Bucking 25-30 mph headwinds we got 41 mpg with driving speeds of +/- 67 mph. I was actually pretty happy about it. Aerodynamics can help only so much and that was some wicked wind. The return trip, with tail wind, averaged 53 mpg.

Oddly enough we haven't driven in much rain, or at night. (Now I'm curious how the interior cabin lighting looks).

It'll be interesting, as everyone's Prius c breaks in and matures, to read posts about mpg evolving and how significantly the elements change those figures.

Deb

 

As others have mentioned, tires have to push out the water. Rain usually come with stronger wind. Headwind is bad, obviously. Sidewind is even worse as it screws up the aerodynamics.

People usually slow down when it rains so you gain some more MPG from it. Overall, the MPG evens out for me.

 

check out my recent trip to daytona. fred and shotys trp to daytona and back
good and bad

 

also in the rain you may be using your A/C to keep the windows defogged that will make a difference as to pull out humidity an A/C unit works Much harder than to cool hot temperatures.. condensing moisture takes a lot of energy...

-Christopher

 

Yep! And so does every other car. The c just lets you know what's really happening.

 

Yep, it rained torrential on hyway and the gas milage got a huge drop for me.

Kinda expected...But driving that little thing through huge pools on the highway in torrential downpours Florida style was kinda scary. That is the trade off I suppose.

 

Have been reading this thread with interest, as in the 10 or so days I have driven my 40 mile commute in the rain over the past 6 weeks, average mileage for the trip has not varied at all. Have been getting a steady 55 to 56 mpg for what is a fairly even split between highway driving at 65-75 MPH and rural/city at 38 - 52 MPH.

Most of the days, the rain was light to medium. Today it was very heavy. Not a lot of puddling or ponding on the road as the drainage was good, but a steady downpour that required full wipers (not intermittent) for the whole trip, and I still got 56mpg. None of the rain on any of my rainy days was accompanied by much in the way of wind.

Obviously, when a tire has to disperse water it's momentum will be lessened, so technically, gas mileage should drop. I can't explain my situation, except possibly that the wind was more a contributor for the others posting here. Also, maybe the fact that the general driving speed was a bit slower overall in the rain, or at least a higher percentage of it was at the lower end of the above speed ranges. That might have negated the lost MPG and balanced it all out.

 

Heavy rain will cause you mpg's to drop anywhere
from 10-15 % or even more. Not just the Prius
but all cars except they don't notice it like
we do in our Priuses.