Ertl M, et al. - Given that meteorological factors seem to influence stroke incidence, researchers conducted this exploratory trial to explore the complex connection between weather and stroke. They analyzed about 18,000 stroke cases from a single stroke center in Southern Germany from 2006 to 2015 and classified into the main subgroups of strokes and subdivisions of ischemic stroke etiologies applying the Trial of Org 10172 in Acute Stroke Treatment classification. The air mass classification was determined from a subset of seven air mass categories for each stroke event. Dry tropical air masses were associated with a lower risk for hemorrhagic (HEM) strokes and a higher risk of macroangiopathic strokes (MAS); these findings were statistically significant. A higher risk for intracerebral bleedings and lower risk for ischemic stroke subtypes was linked to dry polar air masses. A reduced incidence of MAS was linked to moist air masses, while a higher risk of MAS was linked to significant decreases in temperature. Lower risks for MAS and cardio-embolic strokes were related to temperature increases, while a robust temperature increase 5 days before to the event was linked to a lower risk of HEM strokes.