Last updated: January 18, 2025
The climate of South Iceland is characterized by a diverse interplay of Köppen-Geiger climate classifications—specifically Cfc (subpolar oceanic) and ET (tundra). This region experiences a notable temperature range, with minimums dipping to -20°C (-3°F) in December, highlighting the intensity of winter. Conversely, the summer months can reach an average maximum of 24°C (76°F) in July, offering a stark contrast to the frigid winters. Overall, the region's climate is marked by mild summers and cold winters, shaped by its unique geographical and oceanic influences.
In South Iceland, temperature patterns exhibit a distinct seasonal cycle marked by cold winters and milder summers. The winter months from January to March are characterized by average temperatures hovering around 1°C (34°F), with nighttime lows dropping to -18°C (-1°F) in February. As spring arrives in April, a gradual warming trend begins, culminating in milder averages of 4°C (40°F) and maximums reaching 14°C (57°F). The transition into summer brings more significant temperature increases, with July peaking at an average maximum of 24°C (76°F), providing a stark contrast to the preceding months. As autumn sets in, temperatures begin to taper, showcasing fluctuations that range from a cool 16°C (62°F) in September to -20°C (-3°F) by December, indicating the cyclical nature of South Iceland's climate and its stark differentiation between seasonal extremes.
In Vik i Myrdal, temperatures range from a chilly minimum of -11°C (13°F) in April to a warm maximum of 14°C (57°F) in July, as detailed in the monthly temperatures in Vik i Myrdal. Similarly, Vestmannaeyjar experiences a minimum of -8°C (17°F) in February, with a peak of 18°C (65°F) in July, highlighted in the monthly temperatures in Vestmannaeyjar. Selfoss presents a more extreme range, hitting lows of -16°C (3°F) in February and soaring to a high of 24°C (76°F) in July, which can be explored further in the monthly temperatures in Selfoss.
Precipitation in South Iceland displays a notable seasonal pattern, with higher levels recorded during the winter and early autumn months. January and February are particularly wet, with precipitation measuring 164 mm (6.4 in) and 196 mm (7.7 in), respectively, often falling on an average of 15 to 20 days per month. This trend continues into early spring, although there is a slight decrease in March to 146 mm (5.8 in). April maintains elevated levels at 159 mm (6.2 in), while May sees a reduction to 143 mm (5.6 in), signaling the gradual transition toward drier summer conditions.
During the summer, rainfall diminishes markedly, reaching its lowest recorded levels in June and July at 103 mm (4.1 in) and 102 mm (4.0 in), respectively. However, August experiences a slight uptick in precipitation to 110 mm (4.3 in). The onset of autumn brings a resurgence in rainfall, with September witnessing the highest monthly total of 215 mm (8.5 in) over 21 days, contributing to the overall wetter climate of the region. This pattern of variability emphasizes the intriguing balance between moisture and seasons in South Iceland, characterized by a clear distinction between the drier summer months and the much wetter winter and autumn periods.
In South Iceland, sunshine duration showcases a dramatic seasonal fluctuation, with a clear increase as winter transitions into spring and summer. The year commences with minimal sunlight, where January records only 41 hours of sun, a stark contrast to February’s modest rise to 88 hours. March marks a turning point, witnessing a remarkable leap to 185 hours, while April continues the upward trend with 207 hours of sunshine. This trajectory culminates in the peak months of late spring and summer, where May and June shine brightest with 314 and 323 hours respectively, offering nearly a full day’s worth of sunlight each day.
As summer gives way to autumn, the amount of sunshine gradually recedes, yet still remains notable compared to the winter months. July and August follow closely behind June, with 299 and 292 hours of sunshine, ensuring that the warm months are well illuminated. However, September ushers in a significant decrease to 192 hours, a precursor to the diminishing daylight as winter approaches. By the time December arrives, sunlight plummets to just 32 hours, highlighting the lengthy and dark Icelandic winters. This seasonal trend underscores the profound variation in daylight experienced throughout the year, significantly impacting both the climate and lifestyle in South Iceland.
The UV Index in South Iceland exhibits a clear seasonal progression, reflecting the changes in sunlight exposure throughout the year. During the winter months of January and February, the UV Index remains at a low level of 1, allowing for extended outdoor activities with minimal risk of sunburn, as the required burn time is a generous 45 minutes. As spring unfolds, March sees a slight increase to 2, indicating a low exposure category but a hint of increasing risk. This trend continues into April and May, where the index jumps to 4 and 5, indicating moderate UV levels and a reduced burn time of 30 minutes—a signal for individuals to begin taking sun protection measures seriously.
As summer approaches, the UV Index reaches its peak, soaring to 6 in June and July, categorized as high exposure. During this period, the burn time decreases to just 25 minutes, necessitating prompt action for skin protection. In August, the UV Index slightly drops to 5 but remains in the moderate category, while September witnesses a further decline to 3. Finally, as the days shorten in autumn and winter, the UV Index returns to low levels of 1 by November and December, echoing the return of winter’s overarching presence. This seasonal variability underscores the importance of monitoring UV levels in South Iceland to ensure appropriate sun safety measures throughout the year.
UV Risk Categories
Daylight duration in South Iceland demonstrates a striking seasonal variation, heavily influenced by the region's high latitude. In the depths of winter, January offers only 5 hours of daylight, which slightly increases to 8 hours in February. As March unfolds, daylight extends further to 11 hours, heralding the gradual return of light with the approach of spring. By April, the average daylight increases dramatically to 15 hours, and in May, it reaches 18 hours, transforming the landscape and energizing outdoor activities.
The arrival of summer peaks in June, where the region basks in 20 hours of daylight, providing a near-constant glow of sunshine. This abundance of light persists into July with 19 hours before beginning to retreat in August, clocking in at 16 hours. As autumn progresses, daylight duration diminishes to 12 hours in September and continues to decline through October's 9 hours. By the time winter returns, daylight is limited to around 4 hours in December, reinforcing the stark contrast between the vibrant summer months and the darker winter periods in South Iceland. This dramatic shift in daylight not only shapes local activities and lifestyle but also profoundly influences the region's ecosystems.
Hveragerdi, Iceland experiences a subarctic climate characterized by cold winters and mild summers. The average temperature ranges from a low of -1°C (31°F) in January to a high of 24°C (76°F) in July, with significant precipitation throughout the year, peaking in September at 188 mm (7.4 in). While winter months see limited sunshine, totaling only 39 hours in January, the summer months provide more light, with May having 334 hours of sunshine. This combination of temperature and precipitation contributes to the lush landscape for which Hveragerdi is known. For more detailed information, visit Hveragerdi climate.
Selfoss, Iceland experiences a subarctic climate characterized by cold winters and mild summers. Average temperatures range from a frigid -16°C (3°F) in February to a pleasant 24°C (76°F) in July, with precipitation peaking in September at 194 mm (7.7 in). The area enjoys the most sunshine in May, with 334 hours, while December sees only 29 hours of sunlight. Overall, Selfoss offers a diverse climate experience throughout the year, making it an intriguing destination for visitors. For more detailed climate information, visit Selfoss climate.
The climate in Vestmannaeyjar, Iceland, is characterized by cold winters and mild summers. January temperatures range from -5°C (22°F) to 10°C (50°F) with heavy precipitation, averaging around 177 mm (7.0 in). In contrast, the summer months of June and July see milder temperatures between 7°C (45°F) and 18°C (65°F), along with reduced rainfall. The region experiences significant daylight in the summer, with June boasting the highest sunshine at 324 hours. For more detailed information, visit Vestmannaeyjar climate.
Vik i Myrdal, Iceland, experiences a subarctic climate characterized by cold winters and cool summers. January temperatures can drop to -8°C (17°F) with an average of 0°C (33°F), while July peaks at around 14°C (57°F). Precipitation is substantial throughout the year, with February receiving the highest at 347 mm (13.7 in). Sunshine is most abundant in May and June, averaging 308 and 341 hours, respectively, but declines sharply by winter. For more details, visit Vik i Myrdal climate.
In conclusion, the climate of South Iceland is marked by its remarkable seasonal contrasts, with distinct variations in temperature, precipitation, sunshine duration, UV index, and daylight hours. The region experiences cold winters with limited daylight and significant rainfall, transitioning into milder and sunnier summers that illuminate the landscape with long days. This dynamic climatic profile not only influences local weather patterns and ecological systems but also affects the lifestyle and activities of residents and visitors alike. By understanding these seasonal trends, one can appreciate the unique and captivating environment of South Iceland, which thrives amid its dramatic shifts in nature throughout the year.