As of this posting, Wikipedia does not have an entry on cedar fever. The closest thing to it is their entry on hay fever. The entry details the generic symptoms of allergic rhinitis, one of whose causes is the ubiquitous cedar tree.

Cedar fever is triggered by the pollen of the cedar tree. The tiny, hardly visible pollens of wind-pollinated plants like cedar trees are the culprit. In addition to individual sensitivity and geographic differences in local cedar tree populations, the amount of pollen in the air can be a factor in whether cedar fever symptoms develop. Hot, dry, windy days are more likely to have increased amounts of cedar pollen in the air than cool, damp, rainy days when most cedar pollen is washed to the ground.

The time of year at which cedar fever symptoms manifest themselves varies greatly depending on the types of pollen to which an allergic reaction is produced. The cedar tree pollen count is generally highest from January to March.