# Winter vs summer gas--mileage

**URL:** <https://community.cartalk.com/t/winter-vs-summer-gas-mileage/62878>\
**Category:** Maintenance/Repairs\
**Created:** [March 22, 2011, 4:12pm UTC](https://community.cartalk.com/t/winter-vs-summer-gas-mileage/62878 "2011-03-22T16:12:14Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![melott](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/melott/32/10827_2.png) [@melott](https://community.cartalk.com/u/melott)\
**Post date:** [March 22, 2011, 4:12pm UTC](https://community.cartalk.com/t/winter-vs-summer-gas-mileage/62878/1 "2011-03-22T16:12:14Z")

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They switch gas formulas soon in my area.  
  
 Which formulation gives better mileage?  
  
 I would guess summer, but that’s only a guess.

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**Author:** ![mcparadise](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mcparadise/32/32_2.png) [@mcparadise](https://community.cartalk.com/u/mcparadise)\
**Post date:** [March 22, 2011, 4:26pm UTC](https://community.cartalk.com/t/winter-vs-summer-gas-mileage/62878/2 "2011-03-22T16:26:48Z")

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People usually report lower fuel mileage with the winter blends.

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**Author:** ![common-sense-answer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/common-sense-answer/32/716_2.png) [@common-sense-answer](https://community.cartalk.com/u/common-sense-answer)\
**Post date:** [March 22, 2011, 5:24pm UTC](https://community.cartalk.com/t/winter-vs-summer-gas-mileage/62878/3 "2011-03-22T17:24:55Z")

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Government Fuel Economy Link:

[http://www.fueleconomy.gov/feg/factors.shtml](http://www.fueleconomy.gov/feg/factors.shtml)

CSA

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**Author:** ![edb1961](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/edb1961/32/122_2.png) [@edb1961](https://community.cartalk.com/u/edb1961)\
**Post date:** [March 22, 2011, 5:26pm UTC](https://community.cartalk.com/t/winter-vs-summer-gas-mileage/62878/4 "2011-03-22T17:26:24Z")

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I notice a ~10% drop in mileage in the winter. For instance my 2000 Blazer mpg is 16.5 in the winter and ~18 in the summer. My 2010 Cobalt under the same conditions get ~27 winter and 30 mpg in the summer. S. Jersey uses E10 year round, I’m not sure of the differences between the summer and winter blends.

Note: MPG is calculated every third or fourth fill-up (~1k interval).

Ed B.