BR Daily Thermal Amplitude Calculator

Daily Thermal Amplitude (DTR)

Daily thermal amplitude, also called the diurnal temperature range (DTR), is just ΔT = Tmax − Tmin: the gap between the warmest and coldest reading within a 24‑hour stretch. It tells you a lot about local climate, how cloudy a place is and the humidity regime.

Humid coastal sites usually show low amplitudes, around 5–8°C, because water vapour and sea breezes flatten the swing. Head to the semiarid Northeast of Brazil or to high-altitude spots in the Cerrado or the Andean foothills and the dry-season figure often hits 15–20°C. Clear skies let the ground heat up hard by day and cool off fast through radiation at night.

Applications

DTR shows up in crop physiology, where wide swings raise plant water stress and change how sugars build up in coffee, grapes and apples. It also feeds into human thermal comfort, building envelope design, irrigation scheduling and animal husbandry.

FAQ

Why are dry regions colder at night? There's little water vapour to trap the outgoing long‑wave radiation, so once the sun sets the surface dumps its heat to space in a hurry.

Is a high amplitude bad for crops? Not always. Coffee and apples actually do better with cool nights, though a range that's too extreme can stress vegetables and seedlings.

How do I read this calculator? Type the daily Tmax and Tmin (in °C) with a comma between them, and the tool gives back ΔT along with a qualitative classification.