The most active months for lake-effect are December and January, with considerably less activity in the spring and fall. There is a tendency for lake-effect periods (LEPs) to begin within a few hours before and after sunset in the spring (MAM) and fall (SON), with no such diurnal signal observed in the winter (DJF). Lake-effect is slightly more frequent at night than during the day. Overall, the diurnal variability is weaker than found over smaller bodies of water such as the Great Salt Lake of Utah.
Spatial statistics show that the near-shore areas south and east of Lake Ontario received the most frequent lake-effect precipitation. A strong orographic signal was observed over the Tug Hill Plateau, with the maximum in echo frequency on the western (typically windward) side of the plateau. Data from cooperative observer (COOP) sites, as well as the Snow Data Assimilation System (SNODAS), correspond with these radar-derived results described above. These results, combined with a conditional climatology based on environmental parameters, provide a unique perspective on orographic precipitation enhancement in lake-effect systems, with implications for weather forecasting, hydrology, commerce, and public safety on the Tug Hill Plateau and surrounding region.