UV Index Today in Honolulu, Hawaii
Honolulu's UV Climate
Honolulu sits at 21 degrees north latitude — closer to the equator than any other major US city — and its UV levels reflect that: the sun passes nearly directly overhead in summer, and even the 'weak' winter sun delivers UV that would qualify as a summer peak in much of the mainland. Between Waikiki Beach, year-round ocean sports, and a visitor population unaccustomed to tropical sun, Honolulu produces more serious sunburns than almost anywhere in the country.
Average Annual UV Index
9.0
Peak UV Season
Year-round (peak April - September)
Sunny Days per Year
271
Typical UV Index by Season in Honolulu
| Season | Typical Midday UV | Protection Needed |
|---|---|---|
| Summer | Extreme (11+) | SPF 30+, hat, sunglasses; shade from 10 AM – 4 PM |
| Spring & Fall | Very High to Extreme (8-11) | SPF 30+ for extended time outdoors |
| Winter | High (6-8) | Sunscreen for long midday exposure; more on snow |
UV Index in Nearby Cities
- UV Index in Maui, HI94 mi away
Practical Tips for Outdoor Activities
Make the most of outdoor activities while staying safe in Honolulu County:
- Check UV index and weather radar before planning outdoor activities
- Schedule outdoor activities during low UV hours
- Use appropriate sun protection based on UV levels
- Stay hydrated during outdoor activities
- Take regular breaks in shaded areas
- Monitor weather conditions for changes
- Be prepared for sudden weather changes
- Know the signs of heat-related illness
- Wear a hat and protective clothing
- Check visibility conditions before outdoor plans
- Stay alert to weather alerts and warnings
UV and Weather in Honolulu County
Learn about Honolulu County's unique climate patterns, UV radiation levels, and how they affect your daily life. Enter your zip code for location-specific weather radar data and UV forecasts to help you make informed decisions about outdoor activities and sun protection.
Climate and UV Patterns
Honolulu's tropical climate varies remarkably little through the year, and neither does its UV: summer readings hit 11+ (extreme) with regularity, while the winter 'low' season still delivers high-range values of 6-8 at midday. Trade-wind clouds drift over the island daily but are typically thin and fast-moving, providing intermittent shade without meaningful UV protection. There is no month in Honolulu when unprotected midday sun exposure is safe for more than a short period.
UV Index and Health Impact
Understanding UV radiation levels is crucial for protecting your health. Typical clear-day UV index values in Honolulu through the year:
- Summer: Extreme (11+)
- Spring/Fall: Very High to Extreme (8-11)
- Winter: High (6-8)
- Peak UV hours: 10 AM - 4 PM
- Cloud cover can reduce UV by 20-40%, but does not eliminate it
- Clear skies bring maximum UV exposure
Local Weather Patterns
The trade winds define Honolulu's weather: persistent breezes keep temperatures pleasant, which is exactly why visitors underestimate the sun — there's no oppressive heat warning them off the beach at noon. Brief passing showers on the windward side rarely reach Waikiki's leeward shores, where mornings and middays are dependably bright. Water, sand, and light-colored pavement all reflect additional UV, compounding exposure for beachgoers and surfers.
Frequently Asked Questions About UV in Honolulu
What is the UV index in Honolulu today?
The live UV index for Honolulu, HI is shown at the top of this page and updates throughout the day, along with today's maximum and an hourly forecast.
When is the sun strongest in Honolulu?
UV radiation is strongest between 10 AM and 4 PM. Honolulu's peak UV season runs Year-round (peak April - September), when the midday index typically reaches Extreme (11+).
How high does the UV index get in Honolulu?
Summer days in Honolulu typically reach Extreme (11+). Spring and fall usually bring Very High to Extreme (8-11), while winter values are typically High (6-8).
Do I need sunscreen in Honolulu during winter?
Absolutely. Winter UV in Honolulu reaches levels most mainland cities only see in summer, so sunscreen is essential every day of the year.
How sunny is Honolulu compared to other cities?
Honolulu averages about 271 sunny days per year with an average annual UV index around 9.0.