Climate and monthly weather forecastSaint Helier, Jersey
Climate and monthly weather forecast
The climate of Saint Helier
Saint Helier is nested within the geographic confines of Jersey and primarily experiences a Cfb climate classification, as per the Köppen climate system. Boasting a uniquely marine-style west coast weather paired with warm summers, this region presents a medley of mild weather conditions throughout the year.Despite modest temperature variations through the twelve months, the yearly average high temperature lingers around 13.8°C (56.8°F), with the warmest peaks felt in the heart of summer when the mercury can reach 18.2°C (64.8°F). In stark contrast, winter nights do not witness equivalent plunges with the coldest months still maintaining a comfortable level of 6.8°C (44.2°F).
Precipitation is an inherent feature of Saint Helier’s climate. The months of November and December are most susceptible to increased rainfall, recording 78mm (3.07") and 66mm (2.6"), respectively. Concurrently, precipitation is at its lowest between May to August, with an average of 31mm (1.22") of rain experienced per month. Snowfall, on the other hand, is a rare occurrence with only a maximum of 2mm (0.08") reported in February.
One other notable aspect is the humidity which soars high at an average relative level of 80%, reinforcing the moistness of Saint Helier’s climate. This, coupled with persistent moderate winds averaging 32km/h (19.9mph) throughout the year and a generally cloudy sky that conceals the sun for about 40% of the time, underscores the slightly damp and wind-swept nature of Saint Helier's climate.
The best time to visit Saint Helier
Undoubtedly, the summer months from June to August are the best time to visit Saint Helier. During this period, temperatures can hit their yearly peak, reaching 18.2°C (64.8°F) in August. Though accompanied by relatively high humidity levels of about 81%, the heat remains well within comfortable levels. Showers are intermittent, compared to the rest of the year, enhancing the overall desirability of this period.Daylight hours are extensive during these months, extending up to 16.2 hours in June. A hefty dose of sunshine accompanies these expanded days, registering about 9.3 hours in June and July. Avid beachgoers can partake in water activities, thanks to the sea temperature rising to a pleasant 17°C (62.6°F) in August.
The worst time to visit Saint Helier
Traveling to Saint Helier is usually discouraged in late autumn to early winter, especially between November to December, due to the increasing precipitation levels culminating to 78mm (3.07") and 66mm (2.6"), respectively. The temperature also starts to dip from November, registering lows of 10.7°C (51.3°F).The daylight hours witness a noticeable reduction, falling to 9.2 hours in November and 8.3 hours in December. This, combined with a sharp drop in sunshine hours to 4, along with sea temperatures down to 13°C (55.4°F) and 11°C (51.8°F), respectively, which makes water-related activities less enjoyable, makes it a less ideal time for tourists.
Spring weather in Saint Helier
Spring, occurring from March to May, is characterized by slowly rising temperatures, from 9°C (48.2°F) to 13.3°C (55.9°F). Relative humidity remains consistent, around 80%, and the brisk spring winds begin to recede from 27.9km/h (17.3mph) to 22km/h (13.7mph) by May. Rainfall shows a declining trend, descending from 37mm (1.46") in March to 26mm (1.02") in May, making it progressively drier. Sunshine hours linearly increase from 6.4 to 9.3, matching the daylight increments from 11.9 hours to 15.3 hours.Summer weather in Saint Helier
Summers in Saint Helier, from June to August, are comparatively mild, with temperatures hovering between 15.8°C (60.4°F) to 18.2°C (64.8°F). Rain slightly increases from 26mm (1.02") to 42mm (1.65") over these months. However, these wet days are evenly spread out with about 13 rainy days per month, ensuring plenty of dry intervals. Sunshine continues to dominate the sky with 9.2 to 9.7 hours visible each day, whilst the sea temperature escalates, reaching a peak of 17°C (62.6°F) in August.Autumn weather in Saint Helier
Autumn from September to November brings a steady decrease in temperature, from 17.5°C (63.5°F) in September to 12.7°C (54.9°F) in November. Rainfall sharply increases in November to 78mm (3.07"), from a much lower 31mm (1.22") in September, marking the beginning of the wet season. Daylight and sunshine hours gradually decrease from 12.6 to 9.2 hours, and from 8.6 to 4 hours respectively during this period, in tandem with falling temperatures.Winter weather in Saint Helier
Winter in Saint Helier, spanning from December to February, results in lower temperatures, reaching their lowest at 6.8°C (44.2°F) in February. Though light snowfall is a possibility, registering 2mm (0.08") and 1mm (0.04") in January and February respectively, it is by no means a constant feature. Rainfall is heavy at 66mm (2.6") in December but decreases to 48mm (1.89") by February. The amount of sunshine dwindles to 4 hours a day in December and January, while daylight hours slump to their annual low of 8.3 hours in December.Weather in January
Starting the year in Saint Helier, January displays typical winter conditions. It is the period when frigid winds from the eastern half sweep across the city, making the weather exceptionally cold and blustery. Snowfall remains minimal with a record of only 2mm (0.08"). Weather in January »Weather in February
Moving into February, the weather remains consistent with January's cold pattern, albeit with slightly warmer temperatures. As the city is still within the wintry season, frosty winds continue to batter Saint Helier. Despite being a winter month, snowfall is lower than January with only 1mm (0.04") recorded. Weather in February »Weather in March
By March, spring starts to nudge its way into Saint Helier. Temperatures rise steadily, making the climatic conditions more pleasant compared to the preceding months. The thawing effect becomes more prominent with the snowfall almost reaching the verge of extinction with a measly 1mm (0.04"). Weather in March »Weather in April
Come April, the full bloom of spring unravels in Saint Helier, showing up plum blossoms against the backdrop of clear blue skies. The climate is comfortable, with an absence of snowfall. The combination of manageable temperatures and increased sunlight hours creates an idyllic setting. Weather in April »Weather in May
May marks the definitive end of cold weather in Saint Helier. The spring weather starts transitioning into summer, brewing a mild and enjoyable climate. A significant decrease in the rainfall amount is observed, decreasing from 32mm (1.26") in April to 26mm (1.02") in May. Weather in May »Weather in June
June brings the onset of summer in Saint Helier, characterized by higher temperatures and extended daylight hours. Despite being the start of the hotter season, Saint Helier still retains its charm with manageable temperature levels. Weather in June »Weather in July
In July, Saint Helier experiences the peak of summer. The city enjoys its warmest month with the mercury hitting the maximum level of 17.6°C (63.7°F). The rainfall amounts drop, making July one of the driest months. The increased daylight and sunlit hours further amplify summer's appearance. Weather in July »Weather in August
August carries forward July's warm trend but with slightly decreasing temperatures. The city remains firmly within the grip of summer. Despite the reduction, rainfall amounts increase to 42mm (1.65"). As expected, daylight hours start to reduce but remain sufficient for outdoor activities. Weather in August »Weather in September
September initiates the transition to Autumn in Saint Helier. Despite this, temperatures remain pleasantly warm, offering an extended opportunity to enjoy the city's outdoor beauty. The rainfall volume decreases considerably from August's 42mm (1.65") to September's 31mm (1.22"). Weather in September »Weather in October
In October, the palpable arrival of autumn in Saint Helier brings cooler conditions. The pleasant heat of September gives way to chillier weather, making the mornings crisp and afternoons cool. The rainfall level sees a significant rise, almost doubling from 31mm (1.22") in September to 60mm (2.36") in October. Weather in October »Weather in November
November marks the transition into winter again in Saint Helier. As temperatures continually drop, the first signs of a more frigid season are evident. Rainfall reaches its peak with a recorded 78mm (3.07"), making it the wettest month of the year. Weather in November »Weather in December
By December, winter firmly settles in Saint Helier. The temperatures drop further, and the city becomes cold with the advent of the new season. The snowfall, although a marginal 1mm (0.04"), returns, rendering a festive backdrop to the city. Weather in December »Updated: Jan 31, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
In Saint Helier, Jersey, during the entire year, the rain falls for 189 days and collects up to 538mm (21.18") of precipitation.
January through March, November and December are months with snowfall in Saint Helier.
The month with the most snowfall in Saint Helier, Jersey, is January, when snow falls for 0.4 days and typically aggregates up to 2mm (0.08") of snow.
In Saint Helier, Jersey, during the entire year, snow falls for 1.4 days and aggregates up to 6mm (0.24") of snow.
January and November, with an average of 4h of sunshine, are months with the least sunshine in Saint Helier, Jersey.
January and February, with an average maximum UV index of 2, are months with the lowest UV index in Saint Helier, Jersey.
February is the coldest month, exhibiting average temperatures of 9°C (48.2°F) at the peak and 6.8°C (44.2°F) at the base.
February and March, with an average sea temperature of 9°C (48.2°F), are months with the coldest seawater.
In Saint Helier, snow does not fall in April through October.
The months with the highest humidity are June and July, with an average relative humidity of 83%.
With an average of 16h and 12min of daylight, June has the longest days of the year in Saint Helier.
June through September, with an average maximum UV index of 5, are months with the highest UV index.
The month with the least rainfall in Saint Helier is July, when the rain falls for 12.2 days and typically collects 25mm (0.98") of precipitation.
July has the most sunshine of the year in Saint Helier, Jersey, with an average of 9.7h of sunshine.
August is the month when Saint Helier's temperatures reach their peak, with averages of 18.2°C (64.8°F) and lows of 16.3°C (61.3°F).
With an average sea temperature of 17°C (62.6°F), August is the month with the warmest seawater in Saint Helier.
On Sunday, 27. October 2024, at 02:00, Daylight Saving Time ends in Saint Helier, Jersey, and the time zone changes from BST to GMT. The next Daylight Saving Time starts on Sunday, 30. March 2025, at 01:00, and the time zone reverts from GMT to BST.
The months with the lowest humidity in Saint Helier, Jersey, are November and December, with an average relative humidity of 78%.
The month with the most rainfall is November, when the rain falls for 21.2 days and typically aggregates up to 78mm (3.07") of precipitation.
The month with the shortest days in Saint Helier is December, with an average of 8h and 18min of daylight.
Average temperature
Saint Helier, Jersey
The warmest month (with the highest average high temperature) is August (18.2°C).
The month with the lowest average high temperature is February (9°C).
The month with the highest average low temperature is August (16.3°C).
The coldest month (with the lowest average low temperature) is February (6.8°C).
Average pressure
Saint Helier, Jersey
- Average pressure in January:
1016.5mbar - Average pressure in February:
1015.5mbar - Average pressure in March:
1016.3mbar - Average pressure in April:
1015.6mbar - Average pressure in May:
1017.3mbar - Average pressure in June:
1016.9mbar
- Average pressure in July:
1016.8mbar - Average pressure in August:
1016.5mbar - Average pressure in September:
1018mbar - Average pressure in October:
1016mbar - Average pressure in November:
1011.8mbar - Average pressure in December:
1017mbar
The month with the highest atmospheric pressure is September (1018mbar).
The month with the lowest atmospheric pressure is November (1011.8mbar).
Average wind speed
Saint Helier, Jersey
- Average wind speed in January:
32km/h - Average wind speed in February:
31.7km/h - Average wind speed in March:
27.9km/h - Average wind speed in April:
23.1km/h - Average wind speed in May:
22km/h - Average wind speed in June:
21.2km/h
- Average wind speed in July:
20.4km/h - Average wind speed in August:
21km/h - Average wind speed in September:
23.5km/h - Average wind speed in October:
27km/h - Average wind speed in November:
32.5km/h - Average wind speed in December:
34km/h
The windiest month (with the highest average wind speed) is December (34km/h).
The calmest month (with the lowest average wind speed) is July (20.4km/h).
Average humidity
Saint Helier, Jersey
The months with the highest relative humidity are June and July (83%).
The months with the lowest relative humidity are November and December (78%).
Average rainfall
Saint Helier, Jersey
The wettest month (with the highest rainfall) is November (78mm).
The driest month (with the least rainfall) is July (25mm).
Average rainfall days
Saint Helier, Jersey
- Average rainfall days in January:
20.3 days - Average rainfall days in February:
17.4 days - Average rainfall days in March:
15.2 days - Average rainfall days in April:
12.8 days - Average rainfall days in May:
12.2 days - Average rainfall days in June:
13.1 days
- Average rainfall days in July:
12.2 days - Average rainfall days in August:
13.8 days - Average rainfall days in September:
13.3 days - Average rainfall days in October:
17.5 days - Average rainfall days in November:
21.2 days - Average rainfall days in December:
20 days
The month with the highest number of rainy days is November (21.2 days).
The months with the least rainy days are May and July (12.2 days).
Average snowfall
Saint Helier, Jersey
The month with the highest snowfall is January (2mm).
The months with the least snowfall are April, May, June, July, August, September and October (0mm).
Average snowfall days
Saint Helier, Jersey
- Average snowfall days in January:
0.4 days - Average snowfall days in February:
0.4 days - Average snowfall days in March:
0.2 days - Average snowfall days in April:
0 days - Average snowfall days in May:
0 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0 days - Average snowfall days in November:
0.2 days - Average snowfall days in December:
0.2 days
The months with the highest number of snowfall days are January and February (0.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average sea temperature
Saint Helier, Jersey
The best month for swimming (with the highest average sea temperature) is August (17°C).
The coldest months (with the lowest average sea temperature) are February and March (9°C).
Average daylight / Average sunshine
Saint Helier, Jersey
- Average daylight in January:
8h and 48min - Average daylight in February:
10h and 12min - Average daylight in March:
11h and 54min - Average daylight in April:
13h and 48min - Average daylight in May:
15h and 18min - Average daylight in June:
16h and 12min
- Average daylight in July:
15h and 42min - Average daylight in August:
14h and 18min - Average daylight in September:
12h and 36min - Average daylight in October:
10h and 48min - Average daylight in November:
9h and 12min - Average daylight in December:
8h and 18min
The month with the longest days is June (Average daylight: 16h and 12min).
The month with the shortest days is December (Average daylight: 8h and 18min).
- Average sunshine in January:
4h and 0min - Average sunshine in February:
4h and 18min - Average sunshine in March:
6h and 24min - Average sunshine in April:
9h and 18min - Average sunshine in May:
9h and 18min - Average sunshine in June:
9h and 12min
- Average sunshine in July:
9h and 42min - Average sunshine in August:
9h and 18min - Average sunshine in September:
8h and 36min - Average sunshine in October:
5h and 0min - Average sunshine in November:
4h and 0min - Average sunshine in December:
4h and 6min
The month with the most sunshine is July (Average sunshine: 9h and 42min).
The months with the least sunshine are January and November (Average sunshine: 4h and 0min).
Average sunshine days
Saint Helier, Jersey
- Average sunshine days in January:
7.5 days - Average sunshine days in February:
7.8 days - Average sunshine days in March:
13.2 days - Average sunshine days in April:
14.9 days - Average sunshine days in May:
16.8 days - Average sunshine days in June:
15.4 days
- Average sunshine days in July:
16.4 days - Average sunshine days in August:
14.7 days - Average sunshine days in September:
14.2 days - Average sunshine days in October:
10.9 days - Average sunshine days in November:
5.8 days - Average sunshine days in December:
7.3 days
The month with the most sunshine days is May (16.8 days).
The month with the least sunshine days is November (5.8 days).
Average UV index
Saint Helier, Jersey
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are January and February (UV index 2).
Average cloud cover
Saint Helier, Jersey
The months with the most cloud cover are January, November and December (Cloud cover 61).
The month with the least cloud cover is July (Cloud cover 37).
Average visibility
Saint Helier, Jersey
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
