First be sure to remove any stagnant water that may be around your patio or any other place since mosquitoes are attracted to stagnant water and will lay there eggs in the stagnant water.
Then get yourself some citronella candles that you can use when out on your patio. The citronella candles will keep the mosquitoes away.
Planting garlic and rosemary plants near your patio will also ward off mosquitoes and also spray the area around the patio with a mosquito repellent barrier.