Hello.. I am doing a renovation project on a home in Shah Alam area, where design directive is heavily centered around the channeling/harvesting of wind as a source of natural ventilation for the house.

I am having problem in determining the true prevailing wind direction of the site. So far, we are only informed through site visit experiences - the prevailing wind direction is roughly 'felt' to be from the South East, but I feel that this method of observation seems to arbitrary and indeterminate... especially when we need the information to inform a house design that might last for the next (few) decades..

So far the options are these:
1. Get data from local meteorological department.. IT seems that weather reports can be purchased from the dept. Was wondering if anyone has experience on this?
The concern is that meteorological dept. data may be too macro (large scale) to be used in a localized environment where wind direction can be changed and influenced by surrounding buildings..

2. Measure on site: this is the method that I might be keen on. I though of a DIY wind-sock and placing it on site for >6 hours.. taking time lapse shots of the wind sock every x minutes and then manually plotting out wind direction on a wind rose to find out the prevailing direction.

3. Are there some sort of anemometer or wind meter that can be rented for individuals like me?

Hehe.. thanks for any advice.. really!

Aren't wind direction change according to the monsoon season? unless you are sandwich between two high area