In addition to individual sensitivity and geographic differences in local plant populations, the amount of pollen in the air can be a factor in whether hay fever symptoms develop. Hot, dry, windy days are more likely to have increased amounts of pollen in the air than cool, damp, rainy days when most pollen is washed to the ground.Whether or not you are likely to develop allergies is often passed down through families. If both your parents have allergies, you are likely to have allergies. The chance is greater if your mother has allergies.