WEATHER & CLIMATE

Latitude

Distance north or south of the equator; major control of temperature (higher latitude = colder).

Altitude

Height above sea level; temperature falls roughly 6.5 °C for every 1 000 m rise.

Relief (orographic) rainfall

Rain formed when moist air is forced to rise over mountains, cools, condenses and precipitates on the windward side.

Frontal (cyclonic) rainfall

Rain associated with weather fronts where warm and cold air masses meet; warm air rises over cold air.

Convectional rainfall

Rain caused by intense surface heating; warm air rises, cools and forms cumulonimbus clouds (common in tropics and summer thunderstorms).

Rain shadow

Dry area on the leeward side of a mountain range where descending air warms and holds moisture.

Greenhouse effect

Natural process whereby certain gases (CO₂, methane, water vapour) trap heat in the atmosphere; enhanced by human emissions.

El Niño

Periodic warming of the eastern Pacific Ocean that changes global weather patterns (can bring drought to Australia/NZ, heavy rain to South America).

Isobars

Lines on a weather map joining places of equal atmospheric pressure (measured in millibars).

Anticyclone (High)

Area of high pressure; sinking air; usually settled, clear, dry weather.

Cyclone / Depression (Low)

Area of low pressure; rising air; usually cloudy, wet, windy weather.

Maritime climate

Climate strongly influenced by the ocean; milder temperatures, higher rainfall, smaller annual temperature range.

Continental climate

Climate of inland areas; larger temperature extremes, lower rainfall.

Cyclone Gabrielle (2023)

Severe tropical cyclone that caused catastrophic flooding and damage across the North Island of New Zealand.

Barometer

Instrument that measures atmospheric pressure.

Thermometer

Instrument that measures temperature.

Rain gauge

Instrument that measures the amount of rainfall.

Anemometer

Instrument that measures wind speed.