uv index
C1Formal/Technical in weather and health contexts; increasingly common in general media and everyday conversation.
Definition
Meaning
A standard measurement of the intensity of the sun's ultraviolet (UV) radiation at a particular place and time, used to assess the risk of skin damage.
A numerical scale (typically 1-11+) that quantifies the strength of sunburn-producing UV radiation reaching the Earth's surface. Higher values indicate greater potential for skin and eye damage, necessitating more protective measures.
Linguistics
Semantic Notes
Always used with the definite article 'the' (e.g., check *the* UV index). While 'UV' stands for 'ultraviolet', the full term 'ultraviolet index' is less common. It is a singular count noun, but often appears in headlines or short phrases without an article.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Usage is identical. Spelling of related terms follows regional conventions (e.g., UK: suncream/sun protection; US: sunscreen).
Connotations
Identical technical and health-related connotations in both varieties.
Frequency
Equally frequent in weather reports, health advisories, and public service announcements in both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
The UV index is [number/adjective] today.Check the UV index before [gerund phrase].A UV index of [number] means [consequence].Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “N/A”
Usage
Context Usage
Business
Used by tourism, skincare, and outdoor clothing companies in marketing (e.g., 'Protective clothing for high UV index days').
Academic
Used in environmental science, dermatology, and public health research papers discussing solar radiation and its effects.
Everyday
Used in casual planning (e.g., 'The UV index is extreme, so let's go out later.').
Technical
Precise term in meteorology, climatology, and occupational health and safety protocols.
Examples
By Part of Speech
verb
British English
- N/A (Not used as a verb.)
American English
- N/A (Not used as a verb.)
adverb
British English
- N/A
American English
- N/A
adjective
British English
- N/A (Not used attributively as an adjective. Use 'UV index forecast', not 'UV-index forecast'.)
American English
- N/A (Not used attributively as an adjective. Use 'UV index reading', not 'UV-index reading'.)
Examples
By CEFR Level
- Today the UV index is low.
- Wear a hat if the UV index is high.
- You should check the UV index before spending a long time outside.
- The weather app says the UV index will reach 8 this afternoon.
- Due to the exceptionally high UV index, authorities have issued a sun safety warning.
- Sunscreen should be reapplied more frequently when the UV index peaks around midday.
- Climatologists note that the average summer UV index has been rising incrementally over the past decade.
- The formulation of this sunscreen was tested under laboratory conditions simulating a UV index of 12.
Learning
Memory Aids
Mnemonic
Think: **U**V **V**ery Important **Index** – it's a very important index for protecting your skin from UV rays.
Conceptual Metaphor
THE SUN'S STRENGTH IS A MEASURABLE QUANTITY (e.g., 'The UV index is through the roof today.').
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating as 'УФ указатель' (UF ukazatel'), which is incorrect. The correct equivalent is 'индекс УФ-излучения' (indeks UF-izlucheniya) or commonly just 'УФ-индекс' (UF-indeks).
- Do not confuse with a general 'index' or 'показатель' (pokazatel') without the UV context.
Common Mistakes
- Incorrect: 'UV indexes' (plural is standard 'UV indices' or 'UV indexes', both acceptable).
- Incorrect: 'an UV index' (should be 'a UV index' because 'U' is pronounced with a initial consonant sound /j/).
- Incorrect: Using without 'the' in full sentences (e.g., 'UV index is high' should be '*The* UV index is high').
Practice
Quiz
What does a UV index of 11 typically indicate?
FAQ
Frequently Asked Questions
The scale is open-ended, but values of 11+ are considered 'extreme'. In practice, values above 12 are rare at ground level but can occur in high-altitude tropical regions.
No, it varies significantly. It is typically highest around solar noon (midday when the sun is highest in the sky) and lower in the early morning and late afternoon.
It is calculated by national meteorological and environmental agencies (like the Met Office in the UK or NOAA/EPA in the US) using data on ozone levels, cloud cover, and sun elevation.
Yes, especially with prolonged exposure. A low index (e.g., 1-2) indicates low risk, not zero risk. Fair-skinned individuals can still burn after many hours outdoors without protection.