UV Index in Longwood, Saint Helena, Ascension and Tristan da Cunha

Last updated: May 3, 2025

Understanding the UV Index in Longwood, Saint Helena, Ascension and Tristan da Cunha is crucial for safeguarding your skin health against the sun's harmful effects. With an average maximum UV Index peaking at 9 during midday hours, awareness of these levels can help you prevent sunburn and reduce the risk of long-term skin damage. Longwood's BWh climate brings both warmth and high UV exposure, making it essential to monitor these levels daily. By being informed, you can enjoy the beautiful island surroundings while taking the necessary precautions to protect yourself from excessive sun exposure.

Hourly UV Index in Longwood

As the sun rises, the UV Index starts off low at a comfortable 1 from 7:00 AM to 8:00 AM. By 9:00 AM, it jumps to 3, signaling a gradual increase in sun exposure. The intensity peaks around 12:00 PM, reaching an impressive 9, making midday the most critical time for sun safety. As the afternoon unfolds, the index slowly declines; it drops to 7 by 2:00 PM, then further decreases to 4 at 3:00 PM. The later hours offer a gentle reprieve, with values falling to 1 by 5:00 PM and ultimately 0 by 6:00 PM. Remember, during those peak hours, it’s essential to protect your skin!

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
Time	UVI	Category	Time to Burn
07:00	1	low	45 min
08:00	1	low	45 min
09:00	3	moderate	30 min
10:00	6	high	25 min
11:00	8	very high	15 min
12:00	9	very high	15 min
13:00	9	very high	15 min
14:00	7	high	25 min
15:00	4	moderate	30 min
16:00	2	low	45 min
17:00	1	low	45 min
18:00	0	low	45 min
19:00	0	low	45 min

Monthly UV Index Trends in Longwood

Throughout the year, UV Index levels display significant seasonal variations, with extreme levels persisting from January to April and again in September to November. The highest UV Index is recorded in the first four months of the year, peaking at 15, necessitating a cautious approach with a burn time of only 10 minutes. As temperatures rise, the UV Index decreases slightly in May and June, yet still maintains a very high category, allowing for a burn time of 15 minutes. The late summer months, particularly August, report slightly elevated levels before dropping again in the fall. Visitors and residents should take special care during high-risk months, particularly from January to April and September to November, by using appropriate sun protection strategies such as sunscreen, wearing protective clothing, and seeking shade during peak hours to minimize sun exposure and risk of skin damage.

Monthly Maximum UV Index for Longwood, Saint Helena, Ascension and Tristan da Cunha

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Longwood. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Longwood, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare Longwood UV Index with Other Saint Helena, Ascension and Tristan da Cunha Cities

The table above highlights how UV exposure in Longwood compares to other major locations across Saint Helena, Ascension and Tristan da Cunha. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

Longwood's solar exposure compared to other cities in Saint Helena, Ascension and Tristan da Cunha. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Edinburgh of the Seven Seas UVI	14	13	11	7	4	3	3	5	8	10	12	15
Longwood	15	15	13	12	9	8	8	10	11	14	14	15
Jamestown UVI	15	15	13	12	9	8	8	10	11	14	14	15
Half Tree Hollow UVI	15	15	13	12	9	8	8	10	11	14	14	15
Georgetown UVI	14	14	14	13	12	10	10	11	12	13	14	14