Females need blood, and fly silently. Males don't need blood, and they're the ones you hear, so you needn't bother trying to swat them. A stiff breeze can mean that mossies can end up miles from any water source. They go for the heat you give off, and for the carbon dioxide from your breath, apparently. A trick I learned in the tropics was to move your bed about a foot so so from any wall, and place an oscillating fan on a table at the foot of the bed. Have the draught blow a foot or two above you, down the wall, and under the bed. This way, they never find you! (Don't have the fan blowing directly on you, or you'll likely wake up with cramps).