Climate and Weather Conditions: Temperature, Precipitation & Winds

Weather Conditions

Weather conditions: The diversity of climatic types and their combinations responds to a number of factors that condition temperature, the distribution of precipitation, barometric pressure, humidity, and winds.

Temperature and Geographic Factors

The average temperature of a continent decreases from the Equator toward the poles. The region presents thirteen climatic zones, including:

• Hot zone: the intertropical belt.
• Temperate zones: mid-latitude temperate areas.
• Cold zones: mid-latitude cold zones in both hemispheres, extending from about 60° north and south.

Proximity to the sea: Sea coasts and oceans act to moderate temperature and reduce the thermal amplitude of oceanic climates.

Elevation: As elevation increases, temperature typically decreases by about 1 °C every 180 meters. This lapse rate is evident in the altitudinal zonation of the Andes.

Ocean currents: Warm currents soften coastal temperatures, help increase evaporation and atmospheric moisture, and tend to raise coastal humidity. Cold currents originating at the poles cause drops in temperature and can contribute to the formation of coastal deserts.

Climate and Temperature Classification

Climate: The state of the atmosphere through the troposphere at a particular place.

Temperature classification:

• Above +20 °C: warm zone.
• Between 18 °C and 12 °C: temperate zone.
• Less than 12 °C: cold zone.

Precipitation Categories

Precipitation: Areas with more than 1,000 mm per year are considered wet; areas between 1,000 mm and 500 mm are intermediate; areas under 400 mm are considered dry.

Types of Climate

• Warm climates: equatorial, sub-equatorial, tropical, subtropical.
• Temperate climates: oceanic, transition, continental.
• Cold climates: oceanic, continental, polar.

Elements of Climate

The main elements that define climate include:

• Temperature — heat received from the Sun and redistributed by the atmosphere and oceans.
• Atmospheric pressure — the pressure exerted by the gases that compose the atmosphere at any point. Mean sea-level pressure on Earth is about 1013.25 hPa (or millibars).
• Precipitation — any hydrometeors (rain, snow, sleet, hail) that fall from the sky and reach the surface; this excludes virga (precipitation that evaporates before reaching the ground), fog, and dew. The total precipitation at a point on Earth's surface is called rainfall when it falls as rain.
• Winds — the movement of air present in the atmosphere, especially the troposphere. Wind is a weather phenomenon caused by pressure differences, the Earth's rotation (Coriolis effect), and the translational motion of air masses over the ground.

Geographic Factors Affecting Climate

• Latitude — the angular distance between the Equator and a point on the planet, measured in degrees between 0° and 90°; latitude strongly influences solar radiation and temperature regimes.
• Altitude — causes temperature decreases; as noted above, temperature typically decreases about 1 °C every 180 meters of elevation.
• Nearness to the sea and ocean currents — the movement and permanence of large bodies of water moderate coastal climates. Ocean currents, driven by factors such as Earth’s rotation, wind systems, and the configuration of continents and coastlines, play a major role in local and regional temperature and moisture conditions.