| Country | Climate |
| Samoa | tropical; rainy season (November to April), dry season (May to October) |
| San Marino | Mediterranean; mild to cool winters; warm, sunny summers |
| Sao Tome and Principe | tropical; hot, humid; one rainy season (October to May) |
| Saudi Arabia | harsh, dry desert with great temperature extremes |
| Senegal | tropical; hot, humid; rainy season (May to November) has strong southeast winds; dry season (December to April) dominated by hot, dry, harmattan wind |
| Serbia | in the north, continental climate (cold winters and hot, humid summers with well distributed rainfall); in other parts, continental and Mediterranean climate (relatively cold winters with heavy snowfall and hot, dry summers and autumns) |
| Serbia and Montenegro | void |
| Seychelles | tropical marine; humid; cooler season during southeast monsoon (late May to September); warmer season during northwest monsoon (March to May) |
| Sierra Leone | tropical; hot, humid; summer rainy season (May to December); winter dry season (December to April) |
| Singapore | tropical; hot, humid, rainy; two distinct monsoon seasons - Northeastern monsoon (December to March) and Southwestern monsoon (June to September); inter-monsoon - frequent afternoon and early evening thunderstorms |
| Slovakia | temperate; cool summers; cold, cloudy, humid winters |
| Slovenia | Mediterranean climate on the coast, continental climate with mild to hot summers and cold winters in the plateaus and valleys to the east |
| Solomon Islands | tropical monsoon; few extremes of temperature and weather |
| Somalia | principally desert; northeast monsoon (December to February), moderate temperatures in north and hot in south; southwest monsoon (May to October), torrid in the north and hot in the south, irregular rainfall, hot and humid periods (tangambili) between monsoons |
| South Africa | mostly semiarid; subtropical along east coast; sunny days, cool nights |
| South Georgia and the South Sandwich Islands | variable, with mostly westerly winds throughout the year interspersed with periods of calm; nearly all precipitation falls as snow |
| Southern Ocean | sea temperatures vary from about 10 degrees Celsius to -2 degrees Celsius; cyclonic storms travel eastward around the continent and frequently are intense because of the temperature contrast between ice and open ocean; the ocean area from about latitude 40 south to the Antarctic Circle has the strongest average winds found anywhere on Earth; in winter the ocean freezes outward to 65 degrees south latitude in the Pacific sector and 55 degrees south latitude in the Atlantic sector, lowering surface temperatures well below 0 degrees Celsius; at some coastal points intense persistent drainage winds from the interior keep the shoreline ice-free throughout the winter |
| Spain | temperate; clear, hot summers in interior, more moderate and cloudy along coast; cloudy, cold winters in interior, partly cloudy and cool along coast |
| Spratly Islands | tropical |
| Sri Lanka | tropical monsoon; northeast monsoon (December to March); southwest monsoon (June to October) |
| Sudan | tropical in south; arid desert in north; rainy season varies by region (April to November) |
| Suriname | tropical; moderated by trade winds |
| Svalbard | arctic, tempered by warm North Atlantic Current; cool summers, cold winters; North Atlantic Current flows along west and north coasts of Spitsbergen, keeping water open and navigable most of the year |
| Swaziland | varies from tropical to near temperate |
| Sweden | temperate in south with cold, cloudy winters and cool, partly cloudy summers; subarctic in north |
| Switzerland | temperate, but varies with altitude; cold, cloudy, rainy/snowy winters; cool to warm, cloudy, humid summers with occasional showers |
| Syria | mostly desert; hot, dry, sunny summers (June to August) and mild, rainy winters (December to February) along coast; cold weather with snow or sleet periodically in Damascus |
| Taiwan | tropical; marine; rainy season during southwest monsoon (June to August); cloudiness is persistent and extensive all year |
| Tajikistan | midlatitude continental, hot summers, mild winters; semiarid to polar in Pamir Mountains |
| Tanzania | varies from tropical along coast to temperate in highlands |
| Thailand | tropical; rainy, warm, cloudy southwest monsoon (mid-May to September); dry, cool northeast monsoon (November to mid-March); southern isthmus always hot and humid |