In the Köppen climate classification the climate is classified as Am for a tropical monsoon climate. A typical year sees more than of rainfall. Lying on the Gulf of Mexico, Coatzacoalcos has been struck by several hurricanes and tropical storms such as Hurricane Diana in August 1990, Hurricane Mitch in November 1998, Tropical Storm Larry in October 2003, Hurricane Stan in October 2005, Hurricane Dean in August 2007, Tropical Storm Marco in October 2008, Tropical Storm Hermine in early September 2010, Hurricane Karl in mid September 2010, Tropical Storm Matthew in late September 2010, and Hurricane Richard in October 2010. The winter months are cooler and drier than the summer months. Occasionally, cold high pressure cells from North America drift south across the Gulf of Mexico and drive strong Tehuano winds across the Isthmus, with very strong wind concentration taking place in Chivela Pass in Oaxaca.