Claim: You can get just as badly sunburned on a cloudy day as on a sunny one

First requested: July 14, 2026 at 10:18 AM
67%

IsItCap Score

Truth Potential Meter

Moderately Credible

AI consensusWeak

Grader consensus is weak.
Range 50%–70% (spread Δ20).
The graders diverge. Treat the combined score as uncertain and read the sources carefully.
Read analysis summary

OpenAI Grade

0%
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80%
70%

Perplexity Grade

0%
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80%
65%

Google Gemini Grade

0%
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50%
Shareable summary
Verdict: Questionable
  • Clouds block some UV, making exposure slightly less than full sun
  • Hong Kong Observatory: less UV from direct sunlight on cloudy days
/r/fact-check-sunburn-cloudy-day

Analysis Summary

The claim that you can get just as badly sunburned on a cloudy day as on a sunny one is mostly true. Research from dermatologists and health sources indicates that over 90% of UV radiation can penetrate clouds, leading to significant sun exposure. However, some sources note that while UV levels are high, they may not be identical to those on clear days, suggesting a slight reduction in risk. Disputing this, other studies highlight that certain cloud conditions can actually increase UV exposure, making it potentially more dangerous than sunny days in some cases. Thus, caution is advised regardless of cloud cover. The graders interpret the evidence differently, so the score range widens. OpenAI comes in highest (70%), while Gemini is lowest (50%). Perplexity expresses higher confidence than Gemini on this claim. While the majority of evidence supports the claim that sunburn can occur on cloudy days, some sources argue that specific cloud conditions can enhance UV exposure. For instance, the 'broken cloud effect' can increase UV levels, leading to higher risks of sunburn compared to clear skies. This nuance suggests that while the claim holds true in many scenarios, there are exceptions that could affect the overall risk of sunburn. Therefore, the presence of clouds does not eliminate the risk of sunburn, but the degree of risk may vary based on specific weather conditions.
Jump to source analysis

Source quality

Truth (from sources)7.00 / 10
Source reliability7.00 / 10
Source independence6.00 / 10

Claim checks

Fits established facts7.00 / 10
Logical consistency8.00 / 10
Expert consensus7.00 / 10
Related fact checks

Source Analysis

Common arguments
Supporting the claim
  • Over 90% of UV passes through light clouds, causing similar burn risk [1][2]
  • Dermatologist says cloudy exposure is 'very similar' to sunny days [2]
  • Broken cloud effect can raise UV-B 25% and DNA damage 40% above clear skies [3]
Against the claim
  • Clouds block some UV, making exposure slightly less than full sun [1]
  • Hong Kong Observatory: less UV from direct sunlight on cloudy days [3]
  • Burn severity not necessarily identical; 'very similar' but not equal [2]

Mainstream Sources

Publication

Healthline

Title

Yes, You Can Get a Sunburn Even on a Cloudy Day

Summary

More than 90% of UV radiation passes through light clouds, but clouds do block some UV, making exposure slightly less than on a fully sunny day.

Source details

Type: Blog
No Date

URL

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Publication

King 5

Title

Yes, you can get a sunburn on a cloudy day

Summary

A dermatologist states clouds don't block much UV, giving 'pretty much a very similar exposure' to a sunny day, though not necessarily identical severity.

Source details

Type: Major Media
No DateSecondary Reporting

URL

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Publication

Hong Kong Observatory

Title

Do we get sunburned on a cloudy day?

Summary

You won't get as much UV exposure from direct sunlight on a cloudy day as on a clear sunny day.

Source details

Type: Official
No DatePrimary Data

URL

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Alternative Sources

Publication

Dr. Gurgen

Title

Are the Sun's UV Rays Really Stronger on Cloudy Days ...

Summary

The 'broken cloud effect' can raise UV-B rays by 25% and DNA damage by 40% compared to clear skies, making partly cloudy days potentially more dangerous.

Source details

Type: Blog
No DateLow Transparency

URL

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Publication

UV Blocker

Title

Can You Get Sunburn on a Cloudy Day? The 80% UV Myth Most ...

Summary

On partly cloudy days, UV radiation can exceed clear-sky levels by up to 25%, posing a higher threat than a cloudless sky.

Source details

Type: Blog
No Date

URL

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Publication

Weather.com

Title

When It's Cloudy, You Can Still Get A Sunburn

Summary

Thin clouds can amplify UV levels rather than just offering minimal protection, potentially increasing exposure beyond clear-sky baselines.

Source details

Type: Major Media
No DateSecondary Reporting

URL

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Analysis Breakdown

True/False Spectrum (7.0)Source Credibility (7.0)Bias Assessment (6.0)Contextual Integrity (7.0)Content Coherence (8.0)Expert Consensus (7.0)70%

How to read the breakdown

Weakest areas
Independence6.0/10Truth7.0/10
  • Truth: how well sources support the core claim.
  • Source reliability: whether the sources have a strong track record.
  • Independence: whether coverage looks one-sided or recycled.
  • Context: missing details (timeframe, definitions, scope) that change meaning.
  • Tip: if graders disagree, rely more on the summary + sources than the single number.

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Methodology