Glossary of weather terms
Every term behind the forecast, with plain-English definitions written to be understood without a meteorology background. Search, filter by category, and switch between plain and technical wording.
1–24h summary weather code
The most common weather over a chosen period, used to summarise a whole day in one icon.
3D wind vectors (u/v)
Wind split into its east–west and north–south parts at different heights — used in flight planning.
Air temperature at 1.5m
How warm or cold the air is, measured about 1.5m off the ground — the ‘temperature’ you’d see in a normal forecast.
Air temperature at 1.5m – day max
The highest the air temperature is likely to reach during the day.
Air temperature at 1.5m – night min
The lowest the air temperature is likely to fall to overnight.
Clear-air turbulence potential
How bumpy a flight is likely to be in cloud-free air, so routes can avoid the rough patches.
Cloud base height
How high above the ground the bottom of the cloud sits.
Cloud below 1,000 feet
How much low cloud sits below 1,000 feet — important for aircraft and hill fog.
Downward shortwave radiation flux
How much energy from the sun reaches the ground — useful for solar power.
Feels-like temperature
How hot or cold it actually feels once wind and humidity are taken into account.
Geopotential height at 500hPa
The height in the atmosphere where pressure drops to 500hPa — used to track weather systems.
Lightning flash density
How many lightning strikes happen in an area — higher means more thunderstorm risk.
Mean sea level pressure
Air pressure adjusted to sea level — the highs and lows you see on weather maps.
Precipitation rate
How hard it is raining or snowing right now.
Probability of snow
The chance that what falls will be snow rather than rain.
Rainfall rate
How heavily rain is falling, not counting snow.
Relative humidity at 1.5m
How moist the air is, as a percentage — 100% means the air is fully saturated.
Significant weather code
A single code that sums up the main weather — sunny, cloudy, rain or thunder — shown as the forecast icon.
Snowfall rate
How fast snow is falling.
Total cloud amount
How much of the sky is covered by cloud, from clear to completely overcast.
Total precipitation accumulation
The total amount of rain and snow that falls over a chosen period.
UV index
How strong the sun’s UV is, on a scale where higher means you burn faster.
Visibility
How far you can clearly see — low values mean fog or heavy rain.
Wet-bulb temperature
The lowest temperature you can reach by evaporating water into the air — handy for spotting when rain might turn to snow.
Wind direction at 10m
The direction the wind is blowing from, in degrees or compass points.
Wind gust at 10m
The strongest short bursts of wind — the gusts that can catch you out.
Wind speed at 10m
How fast the wind is blowing, measured 10m above the ground.