What is the Sao Luis UV index scale today?
Consult the Sao Luis UV index today to determine whether sun exposure is safe or if precautions should be taken.
Live UV data for Sao Luis is temporarily unavailable — today's modelled peak is about 9.6.
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What's the UV right now in other cities of Brazil (today's UV rays)
Sao Luis Real-Time UV Index Forecast Chart (Hourly Sao Luis UV Index Chart)
Explore the Sao Luis UV index forecast chart for the coming hours to stay informed about the varying levels of ultraviolet radiation throughout the day.
Modelled from today's peak UV — live hourly data is temporarily unavailable.
Safe Exposure Time Calculation (Time to Burn Chart)
The most commonly used scheme to classify a person's skin type by their response to sun exposure — the degree of burning and tanning — was developed by Thomas B. Fitzpatrick, MD, PhD. As a matter of fact, even the skin colours of Emoji characters are based on the Fitzpatrick scale.
| Skin Type | Color | Typical Features | Tanning Ability | Time to Burn (minutes) |
|---|---|---|---|---|
| I | Red or blond hair; light-colored eyes; freckles likely | Always burns, does not tan | 17.36 | |
| II | Light eyes; light hair | Burns easily, tans poorly | 20.83 | |
| III | Any eye or hair color (very common skin type) | Tans after initial burn | 27.78 | |
| IV | Dark brown hair; medium to heavy pigmentation | Burns minimally, tans easily | 34.72 | |
| V | Dark hair; rarely sun sensitive | Rarely burns, tans darkly easily | 55.56 | |
| VI | N/A | Never burns, always tans darkly | 104.17 |
Ultraviolet Radiation Reflection from Surfaces
Highly reflective surfaces — including concrete, snow, glass, water and polished metals — can increase the surrounding levels of solar UV (see source).
| Material | Reflected Solar UV Rays (%) | Effective UV Index | UV Color |
|---|---|---|---|
| New black roadway (Asphalt) | 4.1% | 9.99 | |
| Old grey roadway (Asphalt) | 8.9% | 10.45 | |
| Footpath (Concrete) | 10.1% | 10.57 | |
| Grasslands (Grass) | 1.2% | 9.72 | |
| Lawn (Grass) | 3.5% | 9.94 | |
| Fiberglass boat deck | 9.1% | 10.47 | |
| White house paint | 22% | 11.71 | |
| Wet beach sand | 7.1% | 10.28 | |
| Dry beach sand | 16.5% | 11.18 | |
| Clay/humus (Soil) | 5% | 10.08 | |
| Open water | 3.3% | 9.92 | |
| Open ocean | 8% | 10.37 | |
| Sea surf/white foam | 27.5% | 12.24 | |
| Snow old/new | 69% | 16.22 | |
| Wood boat deck | 6.6% | 10.23 |
Required Sunlight Exposure for Vitamin D in Sao Luis
Vitamin D is a hormone that controls calcium levels in the blood. It is needed to develop and maintain healthy bones, muscles and teeth, and is also important for general health. The human body can obtain vitamin D in two ways: diet or sun exposure.
Minutes of sunlight exposure needed for sufficient vitamin D intake (see source).
| Skin Type | Exposure Time (Sao Luis current UV level: Very High) |
|---|---|
| I | 2-8m |
| II | 5-10m |
| III | 10-15m |
| IV | 15-20m |
| V | 20-30m |
| VI | 30-40m |
