# THI

/ˈθi/ (US) · CEFR C2 · Noun

Source: https://englishreference.com/word/thi
Updated: 2026-05-10

## Definition

Stands for Temperature-Humidity Index. A number that tells you how hot and sticky the weather feels by looking at both heat and humidity. It helps people understand if the weather is dangerous for their health.

For teachers: Abbreviation for Temperature-Humidity Index. A bioclimatic index used to quantify heat stress by combining air temperature and relative humidity. Often used in meteorological and occupational health contexts to assess the risk of heat-related illness.

## Examples

- The THI is very high today, so stay inside.
- Farmers monitor the THI closely during the summer to ensure their livestock do not suffer from heat exhaustion.
- While the ambient temperature remained moderate, a spike in humidity pushed the THI into the danger zone, prompting local authorities to issue a public health advisory.

## Usage notes

- Usually used with the definite article 'the'. Often appears in technical or scientific reports regarding climate and health.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.