Avocado is a subtropical tree and grows very well in semihumid climate. The ideal temperature should be between 16 to 26 Celsius. The trees are very sensitive to frost and high wind. They grow in all type soil with pH ranging from 6 to 7 except it should be well drained.
Please find the attached screen shot showing the ideal conditions to grow avocado.
Considering your region (Bushehr, Borazjan, Iran) where the peak summer temperature reaches around 35 to 45 Celsius and winter temperature around 16 Celsius. Generally the climate is hot and dry. So the warm wind effects the flowers and reduce pollination.
And also soil in Busheh is saline which is detrimental to avocado.