A UV index reading of 8 to 10 means very high risk of harm from unprotected sun exposure.
Take extra precautions because unprotected skin and eyes will be damaged and can burn quickly.
Minimize sun exposure between 10 a.m. and 4 p.m. If outdoors, seek shade and wear sun protective clothing,
a wide-brimmed hat, and UV-blocking sunglasses. Generously apply broad spectrum SPF 30+ sunscreen
every 2 hours, even on cloudy days, and after swimming or sweating.
Bright surfaces, such as sand, water, and snow, will increase UV exposure.
On the ground:
Wind felt on face; leaves rustle; ordinary vanes moved by wind.
On the sea:
Small wavelets, still short, but more pronounced. Crests have a glassy appearance and do not break.
A UV index reading of 11 or more means extreme risk of harm from unprotected sun
exposure. Take all precautions because unprotected skin and eyes can burn in minutes.
Try to avoid sun exposure between 10 a.m. and 4 p.m. If outdoors, seek shade and wear sun
protective clothing, a wide-brimmed hat, and UV-blocking sunglasses. Generously apply broad
spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating.
Bright surfaces, such as sand, water, and snow, will increase UV exposure.
On the ground:
Leaves and small twigs in constant motion; wind extends light flag.
On the sea:
Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses.
On the ground:
Direction of wind shown by smoke drift, but not by wind vanes.
On the sea:
Ripples with the appearance of scales are formed, but without foam crests.
On the ground:
Raises dust and loose paper; small branches are moved.
On the sea:
Small waves, becoming larger; fairly frequent white horses.
Power systems: Weak power grid fluctuations can occur.
Spacecraft operations: Minor impact on satellite operations possible.
Other systems: Migratory animals are affected at this and higher levels;
aurora is commonly visible at high latitudes (northern Michigan and Maine).
A UV index reading of 6 to 7 means high risk of harm from unprotected sun exposure.
Protection against skin and eye damage is needed.
Reduce time in the sun between 10 a.m. and 4 p.m. If outdoors,
seek shade and wear sun protective clothing, a wide-brimmed hat, and UV-blocking sunglasses.
Generously apply broad spectrum SPF 30+ sunscreen every 2 hours,
even on cloudy days, and after swimming or sweating. Bright surfaces, such as sand, water, and snow,
will increase UV exposure.