An ideal kite flying field is flat and broad, with nothing nearby to interrupt the smooth flow of wind. If, like most of us, you live in an area where conditions are often less than perfect, you'll want to find an area to fly which will give you the smoothest, most consistent wind possible. The key is to avoid turbulence.
You'll be able to feel turbulence as an irregular tugging on your line as your kite flies through it, and you may also notice that the dual-line kites have difficulty "hanging" in one place directly overhead or at the edges of the wind window. Single-line kites will be difficult to launch in turbulent wind, and will fly more erratically near the ground where turbulence is worse.
Turbulent air is formed when the wind is disturbed by obstructions in its path, and can occur both downwind and upwind of these obstructions. Upwind turbulence is created as wind builds up in swirling piles in front of buildings, trees, and other objects in its path, seeking a way around to continue its flow. Once the wind has overcome the obstacle, downwind turbulence remains for some distance as the wind struggles to smooth itself out again. We refer to this longer, downwind stretch of turbulence as an object's wind shadow. As a rule of thumb, consider that an object's wind shadow can cover a downwind distance of up to 6 times the object's height - a stand of 50' tall trees can cause turbulence up to 300 feet away! Because wind shadow accounts for the larger portion of the turbulence an obstruction creates, it tends to be the most common type of turbulence you'll encounter while flying. However, if you find yourself having trouble with uncooperative wind when nothing is blocking its path to you, don't forget to check for objects that might be building up turbulence ahead of you as well.
The following diagrams illustrate some of the ways turbulence can occur due to common obstructions you're likely to come across: