The correct placement of the trap is an important factor that heavily influences its effectiveness. Test different locations!
Position the trap in a location that is sheltered from wind, heavy rainfall*, and direct sunlight.
*rainfall will not damage the trap
Ideal locations to position the trap are close to resting areas of mosquitoes such as bushes, shrubs, hedges, or any other foliage. However, placing the trap in very tall grass or under bushes will impair its effectiveness.
The trap should also be positioned close to mosquito breeding sites such as various kinds of temporary stagnant water ranging from small lakes to collections of rain water in rain barrels or old tires. Many mosquitoes do not need a large amount of water for breeding; even a can filled with rain water can be an ideal breeding place.
When CO2 is not available as an attractant it might be a good idea to hang the trap close to a house where CO2 is directed outside from the residents.