Temperatures and seasons

Dew, frost and ice: how to tell them apart at sunrise

A practical guide to recognising dew, hoar frost, frozen dew and clear ice—and what each reveals about the night.

Why clear, calm nights become colder

Learn how radiative cooling, cloud, wind and terrain shape night-time lows and frost risk.

Why can a windscreen freeze when the air is above 0 °C?

Air temperature may stay positive while glass falls below freezing. Learn how radiation, humidity, cloud and wind control morning frost.

Why can the daily minimum temperature occur after sunrise?

Sunrise does not stop cooling instantly. Learn why the daily low can occur after dawn and which factors shift its timing.

UV index on cloudy days: why you can still get sunburned

Clouds do not always block ultraviolet radiation. Learn how to read the UV index and protect yourself on overcast days.

Wet-bulb temperature: what it measures and how to read it

Wet-bulb temperature combines heat with the atmosphere’s capacity for evaporation. Learn what it means and why it is not the same as WBGT.

Snow level and freezing level: why they are not the same

The snow level does not necessarily match the altitude where air reaches 0°C. Here is how the two levels differ and what can move them.

Feels-like temperature: why it differs from air temperature

Air temperature and feels-like temperature can differ. Learn what the index estimates, when wind or humidity matters, and where its limits lie.

Dew, hoar frost and rime: differences and how they form

Learn to tell liquid dew, crystalline hoar frost and rime from freezing fog apart, and what each reveals about conditions near the ground.

Freezing rain, wintry mix and snow: differences and ice risk

Surface temperature alone does not determine what falls. The temperature profile from cloud to ground separates snow, mixed precipitation and freezing rain.

Wind chill explained: why the “feels like” value is not the air temperature

Learn how wind speeds heat loss, what the wind chill index represents and why it cannot cool objects below the actual air temperature.

Frost above 0°C: the difference between air frost and ground frost

Learn why grass can freeze while the forecast remains above 0°C, and how clear skies, wind, moisture and terrain affect the risk.

Temperature inversion: why a valley can be colder than the mountainside

On clear, calm nights, cold air can pool in valleys while slopes stay milder. Learn how an inversion forms and how to interpret local forecasts.