uvExposure: HealthKit quantity type
HKQuantityTypeIdentifierUVExposure · read from Apple’s documentation on 2026-10-02
HKQuantityTypeIdentifier.uvExposure (Objective-C HKQuantityTypeIdentifierUVExposure) is a HealthKit quantity type in Apple's "UV exposure" group. Apple's abstract: “A quantity sample type that measures the user’s exposure to UV radiation.” Apple's discussion says its samples use count units and measure discrete values, so in HKStatisticsQuery it takes .discreteAverage, .discreteMin or .discreteMax. It is available from iOS 9.0 and watchOS 2.0.
What Apple says uvExposure is
A quantity sample type that measures the user’s exposure to UV radiation.
Apple’s abstract, quoted from its uvExposure reference page, read 2026-10-02. Apple’s discussion of the type runs 32 words.
- Swift
HKQuantityTypeIdentifier.uvExposure- Objective-C
HKQuantityTypeIdentifierUVExposure- Family
HKQuantityTypeIdentifier- Apple's topic group
- UV exposure
- Group page
- Environment, hearing and diving
- Apple's reference
- uvExposure on developer.apple.com
Availability
The versions Apple’s documentation data gives for uvExposure, platform by platform, as read on 2026-10-02.
| Platform | Introduced | Deprecated |
|---|---|---|
| iOS | 9.0 | — |
| iPadOS | 9.0 | — |
| Mac Catalyst | 13.0 | — |
| macOS | 13.0 | — |
| visionOS | 1.0 | — |
| watchOS | 2.0 | — |
The rest of that release: HealthKit Types Introduced in iOS 9.
Sum or average, and in which units
Apple states both of these in the prose of the type’s discussion, not as properties, so they are derived from Apple’s sentence and the sentence is shown with each.
Aggregation style
discrete — in an HKStatisticsQuery, use .discreteAverage, .discreteMin or .discreteMax. Apple’s sentence:
These samples use count units (described in ) and measure discrete values (described in ).
Unit family
count — every type in this family is on the HKUnit reference.
Apple states it in the same sentence as the aggregation style, quoted above.
Empty parentheses and a dangling “described in” mark links in Apple’s sentence to other documentation pages: the generator keeps the sentence’s text, not its links, and the quote is left as stored rather than repaired.
Can apps write uvExposure?
Apple’s documentation for uvExposure does not state that its samples are read-only. Apple states read-only status only in prose, and its silence is not a statement either way, so this page makes no claim that apps can save it.
On Android Health Connect
No verified Health Connect counterpart. The cross-platform matrix pairs only metrics checked against both Apple’s and Google’s documentation, and uvExposure is not among them. A similarly named Health Connect record may exist, but a name match is not a verified mapping.
Questions
- Should I sum or average uvExposure in HealthKit?
- Average it, or take its minimum or maximum — do not sum it. Apple's documentation for uvExposure describes it as measuring discrete values, so an HKStatisticsQuery over it takes .discreteAverage, .discreteMin or .discreteMax. Apple's sentence, as read on 2026-10-02: "These samples use count units (described in ) and measure discrete values (described in )."
- Which unit family does Apple give uvExposure?
- Count. Apple's discussion of uvExposure says its samples use count units: "These samples use count units (described in ) and measure discrete values (described in )."
- Which iOS version added uvExposure?
- iOS 9.0. Apple's availability data for uvExposure lists iOS 9.0, iPadOS 9.0, Mac Catalyst 13.0, macOS 13.0, visionOS 1.0 and watchOS 2.0.
Sources checked
- Apple — HKQuantityTypeIdentifier.uvExposure · read 2026-10-02
- Apple — HKQuantityTypeIdentifier · read 2026-10-02
Apple’s abstract and sentences are quoted for identification; the page layout, the capsule and the cross-platform pairing are AIFitnessAPI’s. Generated from Apple’s documentation by scripts/fetch-healthkit-identifiers.mjs, not typed by hand — the same data as the full identifier table.
← All HealthKit type identifiers · Environment, hearing and diving