Pre-seasonal rains, drought, high temperatures and frosts, all are far reaching in their effect on your allergic state of health.
Hay fever resorts will prosper or decline, in accordance with the influence of climatic conditions. In such localities your comfort and relief from symptoms is dependent upon the absence of ragweed or other irritating pollens. Areas in which ragweed pollens are entirely non-existent occur infrequently, but many regions are known in which hay fever pollens are at a minimum. The measurement of pollen concentrations enables scientific observers to determine on which days hay fever sufferers will experience symptoms. The concentrations are in turn influenced by local weather conditions.
As an example we may cite the fluctuating popularity of Lake Placid, N. Y., as a hay fever resort. Persons who went to Lake Placid for relief from their late summer hay fever in 1940 swore by it. In 1941 they and all their friends who went there for the same purpose, swore at it. Why? Weather conditions is the answer. And the evidence for the radical change in hay fever conditions was supplied by the studies of pollen concentrations conducted by the New York State Department of Health. The figures for pollen concentrations in this area indicated 6 days of hay fever in 1938; 8 days in 1939; 2 days in 1940; and 17 days of hay fever in 1941. A hay fever day was one on which the daily pollen count showed more than 25 pollens on a unit area of the pollen slides.
The weather reports supplied the reason for the unpleasant conditions at Lake Placid during 1941. The summer was one of especially dry weather and prevailing high winds.
For more than fifty years, Fire Island, near New York City, had been considered an excellent hay fever resort. But in 1937 the ragweed sensitive vacationers suffered for almost two weeks. It so happened that the State Department conducted a station for that summer on Fire Island. And in a communication to the writer the Department indicated that their pollen counts showed twelve days of hay fever on Fire Island during that season.
There is an absence of plant growth on the island and it is near the ocean. Nevertheless the combination of high velocity winds and an abundance of ragweed pollens from the southern part of Long Island was enough to make the hay fever season of 1937 bad for Fire Islanders.
In these instances we see weather conditions changing pollen concentrations from one locality to another. But on a large scale basis climatic factors are the determiners of plant growth and as such are the greatest influence on seasonal pollen production. Added to this are the observations on the manner in which daily weather conditions influence your day to day hay fever symptoms.
Slow drizzleFog followed by rainLocal thunder showers. Such predictions by the weatherman during the hay fever season brings glee to the hearts of many hay fever sufferers. It is no medieval superstition or neurotic imagination that makes hay fever victims feel relief from symptoms on inclement days. Pollen studies before, during, and after the rains have supplied the reason behind hay fever relief associated with rainy weather.
The pollens attach themselves to the droplets of water and are in a manner of speaking, washed out of the air. Similarly on foggy days the pollens become moistened. In this dampened state they soon settle to the ground. Examinations of pollen slides exposed under these weather conditions show that within a few hours after a steady rain commences there are no pollens in the local atmosphere.
The relief you experience as a result of rain is only temporary. The pollen sacs of the responsible plants do not open when they are damp or wet. But in twelve to twenty-four hours after the rain ceases, the pollen concentrations are up to their previous levels.
In the long run, rain is more of an enemy than an ally to the hay fever sufferer. The amount of pre-season rain determines the size of the ragweed crop. April showers means abundant ragweed which spells much pollen and a long hay fever season. During the hay fever season a certain amount of rain is needed by the plants to continue their pollination. However, if the rains occur in the early morning hours they block pollination for that day. It has been observed by Durham that the ragweed plants pollinate principally during the morning hours.
Absence of rain which takes the proportions of a drought in any one area will not bring absolute relief to ragweed hay fever sufferers. As previously indicated the ragweeds are a hardy plant. They will grow in great enough abundance with one tenth the amount of rain needed by garden vegetables. On the contrary a drought with its dryness, if accompanied by windy weather will spread pollen concentrations to areas ordinarily free from ragweed pollens. Lack of rainfall does help those suffering from early summer hay fever. The growth of grasses is dependent-upon rain to a greater extent than the weeds. In the case of early spring hay fever the droughts have to be of exceptionally long duration to affect pollination of the trees. And in such instances when rain finally occurs it brings on late tree pollination which in turn enhances the grass hay fever.