Winds on the north side of STX

Everyone says east-facing houses and balconies have the best breezes. The wind does consistently come from the east everywhere I have been (we have looked at a LOT of houses in the past two months), so houses tend to be oriented that way. You have to balance the breeze and the view, I guess. One other thing to consider is that the wind can also blow debris (leaves or whatever); we had friends who built their pool directly east of some trees, and spend all day cleaning leaves out of it.

I'm not an expert! Just repeating what I've been told.

Hello, newarrival,

I agree with your observation but if your friends built their pool directly east of the trees then the trees would be behind (west) of the pool. Then where do the leaves come from? Wouldn't that mean the wind was coming from the west instead?

PT

Sometimes the wind comes from the west, north or south. The general prevailing trade winds are from the ENE but winds do shift and they are not constant. That's why we get ash from Montserrat, when the winds are coming from the south. Nature is unpredictable!

Hello, islandjoan,

Yes, I know that but they spend all day cleaning the leaves out - doesn't sound unpredicatable to me.

PT

I just finished looking at wind direction and speed for every hour of (almost) every day in 2005. It looks like most of the time the winds are from the east (about 80 degrees True) or south-east (about 140 deg True). It also appears that there are moderate winds, 24 hours a day and every day of the year (actually, I don't have data for Jan, and part of Sep). Does this sound right... and typical?

So, if you are on the north side of the island, and not on the peak of a hill, do you get these breezes? Is it different on the east end vs the west end of the island?

checkout this website for wind statistics............. http://windfinder.com/windstats/windstatistic_st_croix.htm

The yearly average is from EastSouthEast at 13mph..for St. Croix
and from SouthEast at 12 mph for St. Thomas

Hi Heepajeep,
Now that's a very cool plot! Thanks much. I made my own plot from 2005 data. It roughly agrees, but I like this windfinder plot much better (better graphical summary, and more data). I wish they included the night time data as well (but of course there isn't much wind surfing or sailing at night).

So, here is how I interpret their data:
- roughly 50% of the time (21% + 27%) the winds are from 90-112 deg
- roughly 90% of the time the winds are from 45-135 deg
- VERY rarely are the winds from N, W or S.
That confirms what my data showed (in gross terms).

My next question is about how those winds ride over the island. I don't know how to get this info. But, this info would help me decide if I NEED to build my house on stilts, or could dig it into the mountain. Hmmm, I wonder if I could buy a web based weather station and install it on my land... with a wireless internet link... Maybe a solar panel to power it. Then I could monitor it for the next 10 years (or until a hurricane takes it out!). Looks like I might have many ideas for my Christmas and birthday lists for the next few years...

I would say wind at ground level is very much affected by hills, trees, buildings, etc. Kinda like a river with rocks and logs, etc.
You get eddy currents and still water, you get holes and sand bars and cross currents, all created due to obstacles, etc.
Just because 90% of the water is flowing one way, there are still spots flowing in different directions.

Yup, I got you, heepajeep. That's the way I look at it also. But, air has a different density than water, and I just don't have enough intuition to tell how far away from a blocking hill until you get the wind back. Or, if you're just over the crest of a long smooth hill vs a sharper hilltop, what happens?

It might make a big difference in how I "place" my house. My lot is very steep and is just over the crest of a hill. The crest has a road, and the border of my lot is on that road. I can see the southern shore at one high corner of my lot, and I can see the northern shore along much of the bordering road. There are higher hills at various heights at distances to the east and SE. If I dig the house into the hill, the top of house will be 10-20 feet below the road (that's how steep the lot is). But, if I come straight out from the road then I'll be as high as I can get. I think it will be much more expensive to keep the house high (the house will sit on an ugly steel truss); but I'm guessing that if I dig into the north facing hill (kind of in a bowl with blockage to the east and west) that I'll get no breeze and no view.

I think I need a remote weather station. BTW, I saw a show on astronomy last night. Folks (say, in Conn.) are buying telescopes and having them installed in New Mexico. The telescopes are on az/el gimbals and have internet remote control and video. Very cool. How hard could a remote weather station be...