VENICE, Italy, Aug. 2 (UPI) -- If you're planning a trip to Venice, Italy, avoid times of high sunspot activity -- which appear to alter weather patterns and flood the city, scientists say.
Between October and December, Venice is hit with exceptionally high tides called "acqua altas" that seem to follow an 11-year cycle -- just like sunspots -- showing highest tides when sunspots are most abundant, a study in the Journal of Geophysical Research Atmospheres found.
Researchers at the University of Lisbon, Portugal examined hourly observations of sea levels recorded between 1948 and 2008, which showed extreme tides followed peaks in the sunspot cycle.
Atmospheric records for the same period showed that in "acqua alta" years low-pressure systems bringing heavy rains and high winds moved closer to Venice, while in quiet solar years they remained further south.
The northerly weather systems allow sea levels to rise, while winds blow from south to north, piling up seawater around Venice.
It remains unclear exactly how solar activity is affecting the weather patterns, the study said.