What Time Does the UV Index Drop Below 3?
There is no single time when the UV index drops below 3. It depends on your location, the date and the weather. Read the falling side of today's hourly forecast for the place you will be.
Why a fixed afternoon time does not work
The sun reaches different heights through the year and at different latitudes. Local clocks also differ from solar time. A late afternoon that is low in one city can still need protection in another.
UV usually builds toward the middle of the day and then falls, but clouds can put dips and bumps in the curve. Look beyond the first low reading if you plan to stay outside for several more hours.
How to find today's drop
- Open UV today and choose your place.
- Look at the afternoon side of the main chart.
- Open Hour-by-hour numbers to check the values next to the time labels.
- Find the first afternoon reading below 3 that stays below for the rest of the outing.
- Check the local date and time zone, especially when planning a trip.
You can also start with a destination page such as Los Angeles or New York City. The chart uses the selected destination's local time, even if you are viewing it from elsewhere.
Hourly values are not an exact crossing time
If one hourly value is above 3 and the next is below, the forecast suggests a crossing somewhere between them. It does not give a measured minute at which your surroundings changed. The curve joins hourly estimates to make the day's pattern easier to read.
The chart's colour bands use rounded UV categories, while the table retains decimal values. If you specifically want a value below 3, read the number in the table rather than using a colour edge as a precise threshold.
What 3 means
Three is the usual sun-protection threshold. Falling below it reduces the expected risk; it does not reset the exposure you have already had.
What if it never reaches 3?
Some days stay low throughout. In that case there is no afternoon crossing to wait for. Read the whole curve, then consider how long you will be outside and whether you need extra care for your skin or surroundings.
What if the chart will not load?
Try again or check your national weather service's UV forecast. We do not replace a failed data request with a typical city value. A seasonal average cannot tell you today's drop.
Common questions
Is UV always low after 4 pm?
No. Check the local forecast. A fixed clock time ignores season, latitude and daylight saving time.
Is sunset the same as the drop below 3?
No. The index can fall below 3 before sunset. The gap varies, which is why the hourly forecast is more useful than sunset alone.
Does the number rise again after a cloudy dip?
It can. Follow the remaining hours rather than stopping at the first reading below 3. Read how cloud affects UV for why a cloudy break can mislead.
Sources and further reading
Check today’s UV for your place
This guide is general information about sun safety and isn’t medical advice. Talk to a doctor or dermatologist about your own skin.