Planning trips for the wind - Additon
 

Something i practice whenever possible, is planning my trips around the wind conditions. It could be post-poning a non-urgent errand, to waiting a few hours, but whenever possible, you should avoid a head wind, take advantage of a tailwind, or avoid side winds if they are high enough, and you have the time to spare.
It may fall into the splitting hairs category, but if it if strong enough, the wind can actually make a big difference in your fuel economy, and you should pay attention to it.
If you have the free time, you can take advantage of a nice tail wind, avoid the expense of a strong head wind, or avoid the stress of a strong side wind.

When faced with a 8 hour drive into 30mph headwinds, I'll delay it. It's more than a splitting hairs scenario then.

Observations from
 

where the wind " comes whipping 'cross the plain". I take a north and south return trip daily. Often this comes with a bow wind or stern wind of 20+ mph.
I have come to think of this as vehicle Speed over Ground vs. Speed thru Air. A vehicle speed over ground at a stedy 50 mph with a headwind of 20 mph equals a 70 mph Speed thru Air. A steady vehicle speed of 50 mph with a 20 mph tailwind equals 30 mph Thru the Air speed.
Rather than waiting for "dead" air here (never), I use the time to observe sweet spot rpm vs. driving at LOD vs. drivng at rpm's at, above, and below the 2200 sweet spot of my 2.5 L 1999 Mazda B-2500 truck. I factor in current ongoing aeromods and hypermiling techniques. Helpful knowledge.
Paticularly when you spot the " Mothership " of an approaching supercell ready to drop funnels and hail up to 2+ inches.
Real life help in being able to plot the escape course and drive like hell "DLH".

It's not splitting hairs. I typically see a 5 MPG variation depending on the direction of light 10 to 15 MPH winds.

My coastdown test showed a very significant drag effect from a 5 MPH wind.

Oh yes, forgot to mention, I go slower when pushing a vicious head or sidewind, and go a bit faster when enjoying a tailwind "free ride".

"...ride the wind..." is not just (a) a lyric in a song, nor (b) a cowboy motto.

I always slow my cruise speed down to compensate for strong headwinds.

I haven't ever had the opportunity to do it, living in a relatively light wind area, United States wise; but I would think that for a strong headwind, if you have a tach. in your vehicle, and slow down to match your normal un-windy cruising rpm's; that as long
as your speed wasn't too slow in that you might be lugging, that action would
help you to dial in windy day solutions!

My commute, S(7 miles),W(15 miles),S(5 miles),E(2 miles) in the morning, reverse at night, is almost always in a bad position for the wind. If there is wind, and i am on my normal routine, guarantee, it is affecting me for the worse. Like i said, i do this when i can, but i rarely can.

Unless it's really gusting I don't really pay attention under the logic (?) that the MPG gained with a tailwind will be lost with a headwind, averaging the entire trip anyway. Is this true? If there is a 20mph wind going south and I drive north to the store at 50mph and back south at 50mph, wouldn't it be roughly the same average MPG as going 40mph up and 60mph back?

Does the wind stay the same that long?
If it stays the same, no 50mph both ways would be worse for fuel economy, since the trip against the wind would require a lot of engine power, and the trip with a tailwind would be reducing engine load, which reduces efficiency. Going faster with tailwind and slower against the wind will decrease overall energy requirement from the engine, and increase average efficiency too.