summer MPG
 

Have an '18 Silverado. In winter the city MPG runs apx 18MPG.
Then with hot weather it goes up to 22MPG. Why ? Is it summer VS winter
fuel ? Never travel in winter but summer HWY MPG goes as high as 30MPG
at times & averages high 20's . Thats not a snap shot but over a 100 mile + ride. Did the math & it figures when I refill making the read out spot on.
Comments ?

73 Zeno:smoke:
LFOD !

It takes a lot longer to warm up in the winter so it runs rich longer. Are you taking relatively short trips with it?

The same thing happens with my mostly-electric Chevrolet Volt car. I can get up to 5.5 miles per kWh on warm or hot days, and as low as 4 MPK on cold days, not even counting power used by the heater.

Cold weather and winter driving conditions can significantly reduce fuel economy. Fuel economy tests show that, in city driving, a conventional gasoline car's gas mileage is roughly 15% lower at 20°F than it would be at 77°F. It can drop as much as 24% for short (3- to 4-mile) trips.

Cold weather effects can vary by vehicle model. However, expect conventional gasoline vehicles to suffer a 10% to 20% fuel economy loss in city driving and a 15% to 33% loss on short trips.

The effect on hybrids is typically greater - with fuel economy dropping about 30% to 34% under these conditions. For hybrids, fuel economy typically decreases by 20% to 40% in city driving and 25% to 45% on short trips.

For electric vehicles (EVs), fuel economy can drop roughly 39% in mixed city and highway driving, and range can drop by 41%. About two-thirds of the extra energy consumed is used to heat the cabin. When the cabin heater is not used, EV fuel economy is 8% lower at 20°F than at 75°F. Driving range is about 12% lower.
Why Winter Fuel Economy is Lower

Cold weather affects vehicles in more ways than one might expect:

Engine and transmission friction increases in cold temperatures due to cold engine oil and other drive-line fluids.
It takes longer for an engine to reach its most fuel-efficient temperature. This affects shorter trips more, since a vehicle spends more of a short trip at less-than-optimal temperatures.
Heated seats, window defrosters, and heater fans use additional power.
Warming up a vehicle before starting a trip lowers fuel economy—idling gets 0 miles per gallon.
Colder air is denser, increasing aerodynamic drag on a vehicle, especially at highway speeds.
Tire pressure decreases in colder temperatures, increasing rolling resistance.
Winter grades of gasoline can have slightly less energy per gallon than summer blends.
Battery performance decreases in cold weather, making it harder for the alternator to keep the battery charged. This also affects the performance of the regenerative braking system on hybrids, plug-in hybrids, and electric vehicles.

In severe winter weather, mpg can drop even further.

Icy or snow-covered roads decreases the tire's grip on the road, wasting energy.
Safe driving speeds on slick roads can be much lower than normal, further reducing fuel economy, especially at speeds below 30 to 40 mph.
Using four-wheel drive uses more fuel.



https://www.energy.gov/energysaver/f...y-cold-weather

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Before MAF sensors there was no way to compensate for air density, which changes with temperature.

Colder air has a higher density and while it may mean a little bit more horsepower it also means higher consumption.

Warmer air is a lower density which means less fuel is needed but it also means less power per cylinder.

I always get worse mileage in the winter. I let the car idle until the blue temperature idiot light goes out, and that takes longer when it's cold.