Major wind chill prediction, should I postpone trip?

I would postpone. If you get a flat, for example, it would turn the trip to disaster.

- Alex

 

windchill does not effect cars. that being said, the possibility of breakdown doesn't sound pleasant. there will be a lot of people out that day and everyday. wait for posts from our midwest and canadian friends.

take precautions if you're a senior or have any medical conditions. your car should have appropriate winter supplies including food, water and blankets.

 

Go. Stick to the main roads. If it gets icy, slow down. Everything works fine in the Prius in the cold. I'm a ski instructor who goes out in all kinds of cold weather. Never had a problem other than super deep, unplowed snow in muddy parking lots (my feet got wet and dirty, but the Prius still didn't get stuck).

 

Windchill is for your bare skin, not for the car. Unless you drive with the windows rolled open, or convertible top down, that highway speed doesn't matter.

MPG will suffer, but otherwise the car will be fine. The kind of car you have, Prius or traditional guzzler, doesn't matter. The concerns are about your body in case circumstances force you to be out of the car for an extended period.

 

Lol, the car doesn't care. Actual temperatures of -6F? That's still shorts and T-Shirt weather here if you get up on the slopes. I remember skiing one year when it was -17F out but nice and sunny. Had my jacket open in just my tshirt and a pair of jeans and was still getting hot.

 

There are large areas of the country that deal with temperatures in that range this time of year.
Some of them even have counties as small as Rhode Island

 

Sorry, have to correct you here. The wind chill will make your engine temperature to rise slower (and possibly never reach proper working temp) if the wind is headwind. Think about something warm being exposed at cold ambient temperature with and without air motion. In which case it would loose heat faster?

- -Alex

 

Yes but it effects car by fraction of what it effects people. If actual temp is -6F and windchill is -30F it only means wind of 21MPH which isn’t fast compared to highway driving speeds. And having grill (partially) blocked will minimize effect even more.

I don’t think that at highway driving that temp is even cold enough to effect fuel economy. Except on start or if you use heater to much.

 

I agree.Wind chill will effect metal objects, but less than it would effect people.

- Alex

 

If we really want to get technical, the speed AND the direction of the car in to, or against the wind, makes all the difference. FWIW: Heater makes no MPG difference at highway speed (as AC does).

 

Wind chill will affect any heated object, regardless of material. The familiar index is computed for bare human skin, and isn't correct for other objects.

The engine block is a heated object, due to the fuel burning inside. But it experiences its own 'wind chill' at highway speed all the time, even in what we consider warm weather. The wind speeds listed above are low compared to what is already entering the grill.

Wind chill will not affect unheated objects at the same temperature as the local still air, unless evaporative cooling is also happening. The objects will stay at the air temperature, not chilling down to the 'wind chill index' figure.

 

I’m not sure what’s the limit of Prius but in my old Corolla and other cars too using heater at full blast even on highway driving will get engine temp dropped if outside temperature is -23c or -10F or colder.

 

"...in my old Corolla and other cars too using heater at full blast even on highway driving will get engine temp dropped if outside temperature is -23c or -10F or colder."

1) Old Corolla is not a Prius.
2) Heater used at full blast at highway speed? Really? That must been a helluva rust bucket! Sounds like the old VW Beetles!
3) -10F real temp not to be confused with human skin based wind chill factors
4) If the car can't get up to full temp THEN (and only then), should you take your dog sled...
5) Exactly how did the cooler engine temp actually effect MPG? Please share data.

 

1) I know but it was just an example. I haven’t tested Prius.

2) If you stand outside in cold you want to get hot as fast as you can. And even at full heater blast inside of back windows were still frozen. And maybe we do have a bit of different idea of highway driving I did count driving about 80km/h or 50MPH. No rust holes.

3) Yes actual temperature.

5) Cooler engine temperatures will effect fuel economy maybe not much but they will. I did just mentioned it originally just to be on safe side.

 

Many hardcore hypermilers will strongly disagree, even in less efficient non-hybrids. This cold ambient temperature will cause some reduction in fuel economy, and turning on cabin heat will reduce it even more.

One of the moderators here has even produced an MPG vs temperature plot from his own data.

 

"Many hardcore hypermilers will strongly disagree, even in less efficient non-hybrids. This cold ambient temperature will cause some reduction in fuel economy, and turning on cabin heat will reduce it even more...One of the moderators here has even produced an MPG vs temperature plot from his own data."

Important detail: Hypermiling is not done at 55+MPH highway speeds. Hypermiling is slower than 41 MPH.
BTW: Boston weather forecast calls for highs in the 20s and 30s and lows in the mid to high teens! THAT ain't cold!
So again I ask, how did the cold weather effect your Corolla's MPG? Any actual data?

 

Cold temperatures effect a lot at shorter trips. Or lower speeds. Especially speeds bellow 67km/h or 42MPH where ICE can stop. But at highway driving once it’s fully warmed only things that change are transaxle oil temp, bearing+axle grease temp, and air density (which shouldn’t reduce Prius engine efficiency).

 

I don’t think any of us are talking about the original topic anymore.

 

Baloney. Plenty of folks at CleanMPG.com still hypermile at highway speeds.

Here are numerous pointers discussing why mpg drops in winter. While many other factors are in play, simple ambient temperature is one of the factors:
Why mileage gets worse in winter
Why Don't I Get The EPA Mileage?

And just posted to another thread, courtesy of miscrms: Help! My 2014 Prius v only 30 to 37 mpg
"2) In this EPA test cycle data from Argonne National labs, the effect of dropping temperature from 72F to 20F on highway cycle mpg is:
Jetta TDI: 52.4 -> 43.6 mpg
Prius PHV (discharged battery): 67.9 -> 55.4 mpg
Argonne TTRDC - D3 (Downloadable Dynamometer Database)"