Just another thought to add to the conversation. The best time for cycling to avoid whatever wind may arise is early in the morning. Early morning starts really help, you can get a majority of your miles in before the winds ever pick-up. Traveling west in the early morning is much preferred because the sun is at your back and it lights up the landscape just for your pleasure. So for me, west is my preferred direction, all things considered.

Me too. Sun on your back in the morning, then the sun going down in the evening.
Especially good if you're wild camping and ride till after sunset before finding a place to stop :)

South in autumn, North in spring, works pretty good too...

Prevailing winds (also called trade winds,westerlies,easterlies by sailors)are just that,general wind direction for a given latitude.As you change latitude the general wind direction changes from E-W to W-E and back again,depending how far you are from the equator.

This isn't speculation,it works the same on Jupiter as it does here.Jupiter has bands in it from rotation,some go E-W,some go W-E....just like Earth.

Most of the rocks whirling around our Sun have bands in them if they have some kind of atmosphere.

In general,prevailing winds are caused by the rotation of the Earth(or planet,moon ect.) dragging the atmosphere along with it,the different high and low pressure systems cause by that motion and the weather systems around the planet,which is all rolled up into one big ball...that we...as humans...guess at....

The discusion on percieved wid is interresting. I`ve often been surprised to find (when stopped) that the wind really wasn`t blowing against me when I could have sworn it was. Other times, I`ve been surprised to see flags or other flappy-type indicators blowing in a direction much different from what I would have thought, or not moving at all. One of these days, just for fun, I`d like to take a ride as a passenger in the back of my pickup with my head sticking up over the cab just to see what an "X" MPH wind really feels like in my face.

Mr. Clemens...

Riding east-west or west-east, prevailing winds don't really matter that much. Where they do matter for example is a ride along the Pacific Coast....

Or in the plains where winds mostly blow north-south or south-north, and those sidewinds will do more to deflate your ego then anything else.

thanks for the great weather site

I don't know about the rest of the country, but in the Tucson valley the normal way of things is that the wind blows from the SE in the morning, and from the NW in the afternoon/evening.

Changes when we have weather systems blow in from elsewhere, but that's to be expected. :)

I have climbed both directions, from Rainbow (a few miles west of McKenzie Bridge) heading east and from Sisters heading west. W-E is "badder" than E-W.

The prevailing summer wind pattern in the eastern US is caused by the Bermuda high. S to SW winds, and W to NW for a day or two when a cold front comes through. The occasional low will bring in easterly winds.

Location. Location. Location. Your route was roughly between latitude 30 degrees and 35 degrees. That is in the subtropical belt where the winds don't come from a prevailing direction. As you go further north from 35 degrees north to around 55 degrees north, you hit the westerlies which do have a prevailing direction. If you go south of 30 degrees, you hit the trade winds which tend to blow easterly.

By prevailing winds, people mean that that is the general direction the wind is blowing. It doesn't mean that the wind is always blowing in the direction but, for the most part, they blow towards the east. If you are going to experience strong winds across the plains of Kansas, Nebraska, Colorado or Wyoming (around the 40th parallel on up to the Canadian border), they will come from the west.

pdlamb asks if anyone lost "tree limbs when the wind hit 130 mph last weekend"? Occasionally, the jet stream does scour down to the surface around the 40th parallel (it's about 20 miles north of my current position). We can experience 120 mph winds here along the Front Range of the Rockies. Our summer storms come from the west and move east. We do, occasionally, experience winds from the east but those are generally milder and are on the back side of a low pressure system that is usually preceded by strong winds from the west.

So, yes, the wind does come predominately from the west along the 40th parallel. Are you always going to experience a headwind if you ride east to west? No but you should expect some days of beating up wind. You'll experience far fewer...and far milder...headwinds if you go west to east. Plus, it's a short steep climb from the west coast to the top of the Rockies if you come from the west. It's a long grueling climb from the east.

Wind would not be at the top of my list of factors in picking a direction when crossing the US, but...

On the TA E-W has an advantage wind wise because the wind in the plains is typically out of the SE and the TA goes kind of SE there. Other routes the edge may go one way or the other.

Factors like preferring to get air travel out of the way up front, when you want the sun in your eyes, and how the weather will be better are much bigger factors.

Er, em, well, actually not. Check out the wind roses at the link I gave earlier. Central Kansas (Wichita), choose north or south; it hardly ever comes from the east or west. Omaha, NE, ditto. South central Colorado (Pueblo), it'll mostly come from the southeast, at least in the summer. Lander, WY, southwest in the summer; Rock Springs, yes, there it's from the west.

IIRC, somebody on usenet "proved" that a crosswind feels like a headwind when you're on a bike a while back. Maybe I should dig it up and go through the vector analysis; I didn't believe the math on a casual glance, but it does seem like there's far more headwinds than tailwinds on a bike. I know I thought I was pushing west into a headwind all the way across Kansas, although the few times we turned north I knew that was a tailwind. People going east thought they were fighting a headwind, but the data indicate Kansas winds are usually within 30 degrees of due south, so maybe we were both fooled.

Speaking as a meteorologist/atmospheric physicist, the yearly-averaged prevailing surface for the entire mid-latitudes is from the southwest. This is simply due to the way energy is transported by the atmosphere from the tropics to the poles.

Of course, when on a bike, you don't care what the yearly, mid-latitudinally averaged wind direction is, you care what the wind direction is where you are. That is going to depend not only on the large-scale forcings, but on smaller scale features such as topography and vegetation as well as what season it is. And once you get outside the mid-latitudes (or near its 'edges') you get other interesting effects too, as mentioned by others. Add in baroclinic instabilities (weather systems/eddies) and it's no wonder why 'prevailing winds' have virtually no meaning among non-meteo types.

If you're really interested in the physics, this chapter is a pretty good introduction. Depending on your level of previous knowledge, you may have to read the first 7 chapters.

Ur...um...actually yes. Wind rose for Pueblo in May

http://www.wcc.nrcs.usda.gov/ftpref/...pueblo_may.gif

Wind predominately out of the west/northwest.

Wichita in May

http://www.wcc.nrcs.usda.gov/ftpref/...ichita_may.gif

Predominately south but, if you look closely, more winds out of the west than winds blowing from the east.

Goodland in May

http://www.wcc.nrcs.usda.gov/ftpref/...odland_may.gif

Similar to Pueblo with more of an westerly component than an easterly one.

The other information to look at is speed. In Pueblo, the average wind speed is 5.2m/s or about 11 mph. There's a lot of time when the speed is 11 m/s or around 24mph. In Wichita and Goodland, the speed is a little higher but the wind blowing to the west is of a lower velocity than the wind blowing to the east.

Additionally, the charts are for 24 hours of wind per day. Winds tend to mitigate in the west after night fall. They will freshen up during the day due to the temperature/altitude/pressure differential.

Finally, yes a cross wind can feel like a headwind. Up to 90 degrees from the side on either right or left is going to feel like you are riding into the wind. On the other hand, a wind from the rear up to about 90 degrees on either side of the bicycle is going to feel like a tailwind. Since the major component of the wind is still coming from the northwest as seen in the wind roses, going towards the east is going to be a bit easier. A bicyclist is going to be more of a push from the wind from west to east than from east to west.

When I was a teenager I was fascinated by the weather. In 8th grade I used metal shop to make a wind vane, rain gauge, and anonometer (measures wind speed). I calibrated the anonometer by having my dad drive our car at specific speeds while I held the gauge out the window in front of the windshield and counted revolutions. I also built a wet/dry hydrometer (relative humidity) and a genuine mercury barometer. The local drug store (they don't exist anymore...replaced by CVS, Walgreens, Wallmart, etc.) sold me 5 pounds of mercury for 5 dollars. I was a 13 year old kid in 1968. Today that would probably be illegal. Sad how the world has changed. But I digress.

In college I took meteorology and in my textbook was an amazing photo of a wind direction experiment. A 500 foot tower was erected and different colored smoke could be released at specific altitudes. In the photo, there are three streams of smoke trailing in three different directions all at the same time. The altitudes are 75 feet apart each beginning at 100 feet!

In flying aircraft there is such a thing as ground effect. About 30 feet above the ground, the air density suddenly increases dramatically (as you descend). Pilots must be ready to "punch through" this barrier or risk floating down the runway and running out of tarmac...especially in smaller aircraft. This has nothing to do with cycling but I think it's an interesting fact to know.

I guess my point is there is a lot more going on than most people are aware of...all they need is the curiosity to look past the mundane and suddenly things aren't quite as boring as they appear.

Huh? That looks like the SE to me. The bars go the way the winds come from not the way they go to.

For example http://www.wcc.nrcs.usda.gov/climate/windrose.html says:
This rose shows that the winds at Fresno in April blow from the northwest much of the time.
http://www.wcc.nrcs.usda.gov/climate/fresno_apr.gif

Edit: More info on wind roses at:
http://www.maine.gov/dep/air/meteoro...drosehelp.html

Well that's embarrassing. In my defense wind direction is always given as the direction that the wind blows from in almost all other cases so when some dyslexic scientist switches things around, it's easy to be confused.

I will also add that from more decades of experience than I care to admit, you aren't all that likely to experience a head wind on a bicycle out on the plains of Colorado coming from the southeast. If you want to avoid the dreaded "uphill and into the wind" ride, it's best to be heading east.

hihi, yeah they do look like wind funnels being blown from the opposite direction. Anyway, nice to see you being wrong for once cyccomute! ;) (take that as a compliment)

If it is any consolation, I had to double and triple check myself because I usually find you to be a solid source when it comes to factual information.

That has not been my experience and in the limited looking that I have done I have not seen any data that suggests that. Granted I have only crossed Colorado once and Kansas twice, but I found the winds a mix of S and SE in the in both cases. My understanding was that is the norm for Summer and the opposite direction for Winter with the shoulder seasons being something in between.

this is an excellent resource, may help resolve this in a more spatial sense...

http://hint.fm/wind/

If you want to avoid an uphill and into the wind ride, it might also help to be riding in the early part of the day before it cools off...

There is a business here for someone. When sailboats race across the atlantic, or around the world. They often have the help of weather plotters who relay info about what routes to take to maximize expected weather systems. Of course wind is critical for sailboats, and also they have full freedom to point in any direction to take advantage of such effects. There has to be an actual answer to this question that would be of use, but it seems too complicated for the average person to work out.

Psychologically, one mostly remembers the extremes. Often bad weather comes from the opposite direction of good weather. So someone remembering their trip will remember the bad weather. If the prevailing good weather is west to east, then the storm weather could be the reverse, and it will seem as though the prevailing wind idea is all wrong. Twice I have hit very powerful winds coming out of the east on the Saint Lawrence river in Quebec. Gale force on both trips The fact of prevailing winds from the west did not save me.

I'm with Cyccommute on this one. After 30 years of touring all around the Western states (mostly on a motorcycle) I can tell ya the wind in the afternoon is mostly out of the West. At least the kind that beats you up - or stops you in your tracks when on a bicycle. Pretty consistent all summer long, and not nearly as bad in the morning. I always assumed it was the heating in the afternoon that turns it on.

Spot on. Days of severe headwinds heading west thru Texas and New Mexico in a late spring, and a day with 40 mph tailwind heading east in Ok stays with you forever. And many of us remember Neil G's battle with westerly gales a few years back. Objectivity is the loser.

When I had a plane, nearly always made better time heading east, which is not really relevant to this thread, but still.......

the spiraling winds to the nw of dallas are interesting to see...