Try to time your outdoor activities so that you are outside when the pollen and mold levels are at their minimum. So, if you are going to exercise outside do it in the early afternoon. Windy days will have higher pollen and mold allergen levels. You may wish to stay indoors on windy days. Outdoor activities for allergy sufferers are best during calm days.
Weeds pollinate at sunrise and sundown as air currents turn over.
If you are allergic to weed pollen, calm mid-day activities should be best for you. Drive your car with the windows up during the outdoor allergy season. Also, turn on your air conditioning in the car to decrease your exposure to these allergenic pollens. If you are driving your car with the windows down, then the car you are in is nothing more than a pollen collector. Take your medications wisely.