Are you safe from sun damage
in Boston?
The sun doesn't discriminate by location. Discover how UV radiation varies by month, day, and hour.There is no universally "safe" city.
Explore Your Risk
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Stay Protected
What is the UV Index?
The UV Index is an international standard measurement of the strength of ultraviolet (UV) radiation from the sun at a particular place and time. It helps you understand the risk of sun exposure and take appropriate protective measures.
Low
Minimal sun protection required. Wear sunglasses on bright days.
Moderate
Protection needed. Wear sunscreen, a hat, and sunglasses.
High
Protection essential. Reduce sun exposure during midday hours.
Very High
Extra protection needed. Avoid sun during peak hours (10 AM - 4 PM).
Extreme
Avoid sun exposure. Unprotected skin can burn in minutes.
Peak Hours Matter
UV radiation is strongest between 10 AM and 4 PM. Plan outdoor activities outside these hours when possible.
Clouds Don't Block UV
Up to 80% of UV rays can penetrate clouds. You can still get sunburned on overcast days.
Location-Dependent
UV index varies by latitude, altitude, season, and time of day. Always check local forecasts.
UV Index Over Time
Understanding historical trends helps you prepare for future sun exposure.
Data range: 2001-2024
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When does Boston spike?
UV levels vary dramatically by month. Understanding these patterns helps you plan outdoor activities and sun protection throughout the year.
No monthly data available for this location.
🏖️ Summer Months
Highest UV levels typically occur during summer months when the sun is most direct. Extra protection is essential.
❄️ Winter Months
Don't be fooled by cooler weather – UV rays can still be harmful in winter, especially at high altitudes or near snow.
UV Throughout the Month
See how UV index changes hour by hour throughout an entire month using NASA POWER satellite data. Colored zones show when UV levels cross into different risk categories.
No hourly data available for
🌅 Morning Hours
UV typically starts low in early morning and rises steadily as the sun climbs higher.
☀️ Peak Hours
UV peaks around solar noon (10 AM - 4 PM). This is when protection is most critical.
🌆 Evening Hours
UV drops as the sun sets, but can still be significant in late afternoon.
How do other cities compare?
UV patterns vary dramatically across the globe. See how Boston compares to other cities around the world in terms of sunshine hours and UV exposure.
Monthly UV Patterns Across Cities
Compare average monthly UV index values across different cities. Notice how seasonal patterns vary based on latitude and hemisphere.
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Climate vs. UV Severity Analysis
This chart shows the relationship between sunshine hours and extreme UV days. Circle size represents cloud cover percentage. The ideal quadrant is "Bright & Gentle" – high sunshine with fewer extreme UV days.
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💡 Key Insight
No city is universally safe from UV exposure. Even locations with high cloud cover can experience dangerous UV levels. The key is to plan by month, day, and hour – and always protect your skin when outdoors.
Cloudiest Cities Around the World
Compare average cloud coverage across different cities using NASA POWER satellite data. Cloud cover affects UV exposure—more clouds typically mean lower UV levels.
Data range: 2020-2024
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☁️ High Cloud Coverage
Cities with higher cloud coverage typically experience lower average UV levels, but don't skip sun protection—UV rays can penetrate clouds!
☀️ Clear Skies
Cities with less cloud coverage often have higher UV exposure. Extra precautions are essential in these sunny locations.
City Environmental Profile Comparison
Compare cities across 8 key environmental metrics in a single radial chart. See how UV exposure, cloud coverage, daylight patterns, and seasonal variations differ across locations at a glance.
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📊 UV Metrics
Compare annual mean UV, peak levels, high-UV day frequency, and seasonal patterns between cities.
☀️ Daylight Patterns
Understand how daylight hours and seasonal variation affect outdoor activity planning in different locations.
☁️ Sky Conditions
See how cloud coverage impacts UV exposure potential and overall environmental conditions.
24-Hour Sun Path & UV Intensity
See today's UV intensity visualized as a sun-path ring. The arc's thickness shows UV strength hour by hour, with twilight bands framing dawn and dusk. Plan your outdoor activities around the safest times.
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⏰ Current Time
The slim sweep hand shows the current time. Watch UV levels change throughout the day in real-time.
📏 Arc Thickness
The thicker the arc, the higher the UV index. Easily spot peak hours when extra protection is needed.
🌅 Twilight Bands
Outer bands show civil, nautical, and astronomical twilight. UV can still affect you during these transition periods.
Protect Yourself Every Day
Sun safety isn't about avoiding the sun entirely – it's about understanding your risk and taking appropriate precautions.
Use Sunscreen
SPF 30+ broad spectrum, reapplied every 2 hours
Wear Protection
Wide-brimmed hats, sunglasses, and protective clothing
Time It Right
Seek shade during peak hours (10 AM - 4 PM)