The weather of freshwater biomes varies depending on the type of ecosystem; ponds and lakes enjoy moderate temperatures with seasonal variations, while wetlands generally exist in warmer, humid areas. Some larger bodies of water in biomes, such as lakes and large ponds, influence surrounding air temperature and moisture levels by cycling heat and heat energy into the surrounding air. Others, such as small rivers and streams, derive influence from their environments, changing in physical form and temperature depending on local conditions.
Weather in freshwater biomes varies with the seasons and geographical location. Some ponds and lakes occur seasonally, filling in natural beds with ample spring and summer rainfall. The extra moisture evaporates into the air, moderating temperatures and producing local conditions such as haze and fog. The temperature of water in these aquatic bodies fluctuates with the seasons, changing physical composition. Colder water forms ice in some lakes and ponds during the winter, reducing the activity of organisms within.
The temperature and conditions of streams and rivers varies, fluctuating with the seasons and location. Stream sources, which often pull water from deep within the Earth, feature cooler temperatures than mouths. Streams and rivers appear around the world, existing in cold, northern climates, moderate conditions and warm, humid locations.