Climatology or climate science is the scientific study of Earth's climate, typically defined as weather conditions averaged over a period of at least 30 years. Climate concerns the atmospheric condition during an extended to indefinite period of time; weather is the condition of the atmosphere during a relative brief period of time. The main topics of research are the study of climate variability, mechanisms of climate changes and modern climate change. This topic of study is regarded as part of the atmospheric sciences and a subdivision of physical geography, which is one of the Earth sciences. Climatology includes some aspects of oceanography and biogeochemistry.

जलवायु विज्ञान (climatology) भौतिक भूगोल की एक शाखा है जिसके अंतर्गत सम्पूर्ण पृथ्वी अथवा किसी स्थान विशेष की जलवायु का अध्ययन किया जाता है।