Weather in Saint Helier

To make your trip to Saint Helier as comfortable as possible, check out the latest weather information. In this section, you will find fresh data, forecasts, and useful charts.

The climate in Saint Helier can be characterised as temperate maritime. This means that mild weather awaits you here without sharp temperature fluctuations throughout the year. Summers are usually warm but not sweltering, while winters are cool but without severe frosts. The influence of the Atlantic Ocean makes the climate humid, so precipitation is possible at any time of the year.

Four seasons are quite clearly defined in Saint Helier. Winter (December-February) is characterised by average temperatures of around 8-10°C and is the wettest period in terms of the number of rainy days, reaching 18-20 per month. Spring (March-May) brings gradual warming, with air temperatures rising to 10-13°C, while the amount of precipitation and cloudy days decreases. Summer (June-August) is the warmest and sunniest time of the year, with average temperatures of 15-18°C and the fewest number of rainy days (8-10 per month). Autumn (September-November) brings gradual cooling, and the number of rainy days increases again, especially in October and November.

Although the total amount of precipitation in millimetres is not very high (from 1 to 5 mm per month), it is worth noting the frequency of rainy days, especially from October to January. The summer months, from July to August, offer the most comfortable weather with maximum temperatures around 18-19°C and the lowest probability of precipitation. In general, the weather in Saint Helier is conducive to visiting all year round, but for sunny days and outdoor activities, the summer months are best suited.

The temperature regime in Saint Helier is distinguished by its mildness and the absence of sharp changes throughout the year. The annual temperature range here is quite moderate. The coldest months are traditionally January and February, when the average air temperature hovers around 8.4-8.5°C. Minimum night-time temperatures during this period can drop to 7.3-7.5°C, and daytime highs rarely exceed 9.5°C. Conversely, the peak heat occurs in August, which is considered the hottest month with an average temperature of 17.8°C and average maximum daytime values of around 18.9°C. This suggests that even in the height of summer, exhausting heat is not characteristic of Saint Helier.

The summer months, from June to August, give residents and guests of Saint Helier pleasant, comfortable warmth. Average daytime temperatures during this period vary from 15.4°C in June to 17.8°C in August. Maximum values usually stay within the range of 16.5°C - 18.9°C, which creates ideal conditions for long walks, relaxing on the coast, and enjoying outdoor activities without feeling intense heat. Nights also remain warm, with minimum temperatures ranging from 14.2°C to 16.7°C, making evening pastimes particularly pleasant.

The winter period, covering the months from December to February, is characterised by cool but mild weather. Monthly average temperatures at this time of year range from 8.4°C (January) to 9.7°C (December). Night-time temperatures rarely drop below 7.3°C, and daytime highs usually reach 9.4°C - 10.8°C. An important feature of the climate in Saint Helier is the insignificant temperature fluctuations between day and night hours. The difference between the average minimum and average maximum temperature within a 24-hour period throughout the year is only about 1-2.5°C. This indicates the stability of the maritime climate and the absence of sharp temperature spikes, making a stay in the city comfortable at any time of the day.

Precipitation in Saint Helier is distributed throughout the year, however, its character and frequency change noticeably depending on the season. Although the total amount of precipitation in millimetres remains relatively low year-round, varying from 1 to 5 mm per month, the number of rainy days undergoes more significant changes. In general, one can distinguish a wetter period in terms of rain frequency, falling on the autumn-winter months, and a drier one in late spring and summer.

The greatest amount of precipitation, at 5 mm each, falls in October, November, and December. These same months, along with January, are also characterised by the highest frequency of rainy days. Thus, in December there are on average 20 rainy days, in November – 19, and in January and October – 18 each. Given the small total amount of precipitation, this suggests that rains during these periods are most likely in the nature of light drizzle or brief showers, rather than heavy downpours. Snow is uncharacteristic for Saint Helier due to the mild maritime climate.

The driest months by precipitation amount are May and July, when only 1 mm falls. These same months also see the lowest number of rainy days: in July there are on average 8, and in May and June – 9 each. This makes the summer period the most favourable for those who prefer sunny weather. Nevertheless, even in the driest months, the probability of rain is not completely excluded, so light protection against precipitation may come in handy.

When planning a trip to Saint Helier, it is important to choose the right wardrobe to feel comfortable in any weather. Given the temperate maritime climate of Jersey, the key principle is layering. Even in the warm months, evenings can be cool, and the weather changeable. Be sure to take a light waterproof and windproof jacket or a raincoat, as despite the small total amount of precipitation, rainy days, especially from October to January, happen often. Don't forget comfortable shoes for walking around the city and its surroundings, as well as a compact umbrella.

In the summer months (June-August), when the average temperature stays around 15-18°C, you will need T-shirts, light trousers, shorts and, of course, sunscreen and sunglasses. However, even in summer, a cardigan or light sweater will not be amiss for evening walks. In spring (March-May) and early autumn (September-October), the weather is pleasant but cooler, so it is worth adding jeans, warm tops, and perhaps a light scarf to your summer set. In winter (November-February), when the temperature drops to 8-10°C, and the number of rainy and windy days increases, you will need warm sweaters, insulated trousers, a hat, gloves, and a more substantial waterproof jacket. Regardless of the season, remember that the weather on the island can change quickly, so readiness for various conditions is the key to a pleasant journey.