Climate and monthly weather forecast
Alderney, Guernsey

Alderney, Guernsey, lays predominantly in the Köppen climate classification zone, wherein it experiences temperate weather, signified by warm summers and mild winters. Posited within the English Channel, the island maintains a persistent maritime influence, which prevents extreme variations in weather throughout the year.

On average, sea temperatures fluctuate between 9.3°C (48.7°F) during the cooler months and peak at 17.4°C (63.3°F) during warmer periods, providing a comfortable environment for marine life and facilitating pleasant coastal activities for visitors. The available daylight hours also demonstrate a noticeable shift from a minimum of 8.2 hours in winter to a maximum of 16.2 hours during the height of summer, significantly affecting the local lifestyle and tourism.

It's noteworthy that, irrespective of the season, Alderney experiences a consistent marine impact, furnishing the island with steady precipitation throughout the year. The variation in climatic factors makes the location interesting from a meteorological perspective as it provides unique weather patterns.

Alderney proves most inviting to visitors during the summer period, specifically between July and August. During this time, sea temperatures reach an enticing 17.2°C (63°F) to 17.4°C (63.3°F), making water-based activities an irrefutable draw. Furthermore, daylight extends to a generous 15.8 to 16.2 hours, empowering tourists with more time to explore the unparalleled landscapes. These factors align, forming a perfect canvas for locals and travelers to relish outdoor pursuits while basking in the bright summer.

Visitor numbers tend to dwindle during the freezing months of January to March. This period brings sea temperatures down to 9.3°C (48.7°F) to 10.1°C (50.2°F), limiting opportunities for water-based activities. Moreover, the scarcity of daylight, averaging from 8.2 to 10.1 hours, affects outdoor exploration, making this time less attractive to potential visitors.

Spring in Alderney is gradual and progressive, characterized by a steady rise in sea temperatures and daylight hours. From March to May, sea temperatures climb from 10.3°C (50.5°F) to 13.8°C (56.8°F), whereas daylight hours extend from 11.9 to 15.4 hours. This extended daylight and warming seas mark the onset of the outdoor activity season, enticing locals and visitors alike.

Summers in Alderney are relatively warm and long, further enriched by extended daylight hours. With sea temperatures peaking from 15.7°C (60.3°F) to 17.4°C (63.3°F) between June and August, it is the perfect time for swimming and water-based activities. Plus, the luxurious 15.8 to 16.2 daylight hours ensure ample time for exploration and relaxation in the island's natural beauty.

As autumn sets in, Alderney witnesses a gradual decrease in sea temperatures and daylight hours. Between September and November, seas cool down from 17.4°C (63.3°F) to 14.5°C (58.1°F), and daylight hours are reduced from 12.6 to 9.1 hours. Despite the lowering temperatures, the landscape's vibrant autumnal hues provide an appealing backdrop for outdoor activities, making it an appealing season for nature lovers.

Alderney’s winter periods are marked by the coldest sea temperatures and shortest daylight hours. From December to February, sea temperatures hover around 9.3°C (48.7°F) to 12°C (53.6°F), and daylight shrinks to merely 8.2 to 10.1 hours. Nonetheless, the mild temperate zone climate prevents harsh winter conditions, ensuring the island retains much of its charm even during this dormant season.

January in Alderney, Guernsey, sees notably reduced hours of daylight, plunging depths of winter. On average, a fairly brief stint of sunlight graces Alderney, as daylight hovers around 8.7 hours per day. Sea temperatures record a cooling trend from the preceding month, offering chilly waters for the brave. Weather in January »

The weather in Alderney sees some change in February. An increase in daylight hours infuses a spark of optimism despite the cold, with average hours reaching approximately 10.1 per day. The growth in daylight would serve as a harbinger to the impending spring. Weather in February »

Entering March, Alderney witnesses a further growth in daylight hours, casting a quieter winter aside as spring begins to bloom. Noticeably longer days set the stage for milder weather, with average daylight increasing to 11.9 hours. Weather in March »

April in Alderney is characterised by greater daylight availability signifying the arrival of the spring season in full swing. A significant jump in daylight hours is observed, with averages decreasing to 13.8 per day, further betraying the retreat of winter. Weather in April »

May carries forward the positive weather trends observed in April in Alderney. The city becomes bathed in sunlight for no less than 15.4 hours a day on average, manifesting the fullness of spring and the looming arrival of summer. An equally remarkable uptick occurs in sea temperatures surging to a more tepid 11.8°C (53.2°F), enhancing the allure of outdoor sea activities. Weather in May »

June marks the onset of summer in Alderney, graced with the longest daylight hours of the entire year. The city basks under the sun for a maximum of 16.2 daylight hours, lending to lovely bright and lengthy days. The sea temperature also cooperates with a pleasant rise to 13.8°C (56.8°F), further enhancing Alderney's summer appeal. Weather in June »

The heart of summer in Alderney ushers in July, carrying forward the extended daylight hours from June, though slightly reduced to 15.8 on average. However, what is noteworthy about July is the sea temperature reaching its highest annual level at a warm 15.7°C (60.3°F). Weather in July »

August in Alderney perseveres with the trend of comfortable summer weather. There are still long stretch of hours under the sun, claiming a substantial 14.4 daylight hours on average. Sea conditions remain inviting, with temperatures hovering around 17.2°C (63°F). Weather in August »

September begins to signify the end of summer, ushering Alderney into the first hints of autumn. A marked drop is exhibited in daylight hours, coming down to an average of 12.6 per day. There's a minimal shift in sea temperature hovering at 17.4°C (63.3°F), exhibiting the highest sea temperature. Weather in September »

Cooler shades of weather start to settle in Alderney as October takes charge, signalling that autumn is in the air. Daylight hours calibrate down to nearly 10.8 per day, continuing the decreasing trend from September. Sea temperatures also tune down to a cooler 16.3°C (61.3°F), correlating with the onset of chillier weather. Weather in October »

November in Alderney sees a dramatic reduction in daylight that foreshadows the advent of another winter season. The sunlight duration decreases further to a total of 9.1 daylight hours, resulting in a greater presence of cooler temperatures. Weather in November »

December brings the onset of winter in Alderney, noticeable through the significant drop in daylight hours. Alderney receives the least amount of daylight for the year in this month, playing host to just 8.2 hours. The frigid sea temperature further confirms winter’s arrival, falling to a brisk 12°C (53.6°F). Weather in December »