Climate and average weather in Saint Helier
In Saint Helier, the summers are mild, showery, and partly cloudy and the winters are cool, windy, and mostly cloudy.
Over the course of the year, the temperature in Saint Helier typically varies from 7°C to 18°C, and is rarely below 3°C or above 21°C. August is the hottest month of the year, while February is the coldest.
Based on the travel score, the best time of year to visit Saint Helier for warm-weather activities is from mid June to late September.
- Hottest
- Aug
- 18°
- Coldest
- Feb
- 7°
- Wettest
- Dec
- 138 mm
- Driest
- Jul
- 48 mm
- Rain / yr
- 1000 mm
- 149 wet days
- Daylight
- 8.0–16.0 h
- shortest–longest
- Elevation
- 11 m
- 49.2°N
- Clearest
- Jul
- 52% cloud
Saint Helier is one of the twelve parishes and capital of Jersey in the Channel Islands.
- Density
- 2,642/km²
- people per km²
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Saint Helier weather by month, at a glance
The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.
Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around mid June to late September.
Temperature through the year
Daily average highs and lows in Saint Helier, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 3.7 months, from June 19 to October 8, with daily high temperatures above 16°C. The hottest month of the year in Saint Helier is August, with an average high of 18°C and low of 17°C.
The cool season lasts 4.0 months, from December 8 to April 8, with daily high temperatures below 10°C. The coldest month of the year in Saint Helier is February, with an average low of 7°C and high of 9°C.
Days typically run about 2°C warmer than nights year-round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 9 | 9 | 9 | 11 | 13 | 16 | 18 | 18 | 17 | 15 | 12 | 10 |
| Avg low (°C) | 7 | 7 | 8 | 9 | 11 | 14 | 16 | 17 | 16 | 13 | 10 | 8 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| Jan | 9 | 7 |
| Feb | 9 | 7 |
| Mar | 9 | 8 |
| Apr | 11 | 9 |
| May | 13 | 11 |
| Jun | 16 | 14 |
| Jul | 18 | 16 |
| Aug | 18 | 17 |
| Sep | 17 | 16 |
| Oct | 15 | 13 |
| Nov | 12 | 10 |
| Dec | 10 | 8 |
Average hourly temperature in Saint Helier
A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on August afternoons, near 18°C, and coldest before dawn in February, near 7°C.
Saint Helier weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 9° / 7° | 110 | 15.8 | 8.5 | 1.5 |
| Feb | 9° / 7° | 81 | 12.9 | 9.8 | 1.4 |
| Mar | 9° / 8° | 69 | 12.4 | 11.6 | 1.9 |
| Apr | 11° / 9° | 57 | 10.5 | 13.4 | 2.7 |
| May | 13° / 11° | 53 | 9.4 | 15 | 3.8 |
| Jun | 16° / 14° | 50 | 8.7 | 15.9 | 5.0 |
| Jul | 18° / 16° | 48 | 9.1 | 15.6 | 6.0 |
| Aug | 18° / 17° | 63 | 9.8 | 14.2 | 6.1 |
| Sep | 17° / 16° | 77 | 11 | 12.4 | 5.5 |
| Oct | 15° / 13° | 122 | 15.5 | 10.5 | 4.0 |
| Nov | 12° / 10° | 132 | 17.6 | 8.9 | 2.7 |
| Dec | 10° / 8° | 138 | 16.7 | 8.1 | 1.9 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Saint Helier gets about 1000 mm of precipitation a year. On a typical day the chance of rain is often wet, but that rises and falls sharply with the seasons.
The wetter season lasts 5.5 months, from around Sep 24 to Mar 9, peaking in November at about 60% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jul 22.
December is the wettest month by volume, with 138 mm over about 17 wet days; July is the driest, with 48 mm.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 51 | 46 | 39 | 34 | 31 | 30 | 29 | 31 | 37 | 50 | 58 | 54 |
| Rain days | 16 | 13 | 12 | 11 | 9 | 9 | 9 | 10 | 11 | 16 | 18 | 17 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 51 | 16 |
| Feb | 46 | 13 |
| Mar | 39 | 12 |
| Apr | 34 | 11 |
| May | 31 | 9 |
| Jun | 30 | 9 |
| Jul | 29 | 9 |
| Aug | 31 | 10 |
| Sep | 37 | 11 |
| Oct | 50 | 16 |
| Nov | 58 | 18 |
| Dec | 54 | 17 |
Monthly rainfall
Over a full year, Saint Helier collects about 1000 mm of rain across 149 wet days — roughly 83 mm in an average month.
It doesn’t fall evenly. December is the wettest month with 138 mm, while July is the driest at just 48 mm. The three wettest months alone bring about 39% of the year’s total.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (mm) | 110 | 81 | 69 | 57 | 53 | 50 | 48 | 63 | 77 | 122 | 132 | 138 |
| Rain days | 16 | 13 | 12 | 11 | 9 | 9 | 9 | 10 | 11 | 16 | 18 | 17 |
| Rainfall (mm) | Rain days | |
|---|---|---|
| Jan | 110 | 16 |
| Feb | 81 | 13 |
| Mar | 69 | 12 |
| Apr | 57 | 11 |
| May | 53 | 9 |
| Jun | 50 | 9 |
| Jul | 48 | 9 |
| Aug | 63 | 10 |
| Sep | 77 | 11 |
| Oct | 122 | 16 |
| Nov | 132 | 18 |
| Dec | 138 | 17 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Saint Helier, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around May 6 and lasts for 4.8 months, ending around September 29. The clearest month is July, when the sky is clear, mostly clear, or partly cloudy 57% of the time on average.
The cloudier part of the year begins around September 30 and lasts for 5.8 months, ending around March 25. The cloudiest month is January, when it is overcast or mostly cloudy 73% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 27 | 32 | 37 | 48 | 45 | 51 | 57 | 55 | 49 | 36 | 31 | 27 |
| Cloudier (%) | 73 | 68 | 63 | 52 | 55 | 49 | 43 | 45 | 51 | 64 | 69 | 73 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 27 | 73 |
| Feb | 32 | 68 |
| Mar | 37 | 63 |
| Apr | 48 | 52 |
| May | 45 | 55 |
| Jun | 51 | 49 |
| Jul | 57 | 43 |
| Aug | 55 | 45 |
| Sep | 49 | 51 |
| Oct | 36 | 64 |
| Nov | 31 | 69 |
| Dec | 27 | 73 |
Daylight, sunrise and sunset
Hours of daylight through the year, with sunrise and sunset times.
The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 13, brings about 16 hours of light; the shortest, around December 13, only 8 hours — a swing of roughly 8 hours.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 8.5 | 9.8 | 11.6 | 13.4 | 15.0 | 15.9 | 15.6 | 14.2 | 12.4 | 10.5 | 8.9 | 8.1 |
| Sunrise (AM) | 8:05 | 7:29 | 6:32 | 5:25 | 4:32 | 4:09 | 4:25 | 5:06 | 5:52 | 6:38 | 7:28 | 8:04 |
| Sunset (PM) | 4:30 | 5:17 | 6:05 | 6:52 | 7:37 | 8:08 | 8:03 | 7:19 | 6:13 | 5:09 | 4:19 | 4:05 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 8.5 | 8:05 | 4:30 |
| Feb | 9.8 | 7:29 | 5:17 |
| Mar | 11.6 | 6:32 | 6:05 |
| Apr | 13.4 | 5:25 | 6:52 |
| May | 15.0 | 4:32 | 7:37 |
| Jun | 15.9 | 4:09 | 8:08 |
| Jul | 15.6 | 4:25 | 8:03 |
| Aug | 14.2 | 5:06 | 7:19 |
| Sep | 12.4 | 5:52 | 6:13 |
| Oct | 10.5 | 6:38 | 5:09 |
| Nov | 8.9 | 7:28 | 4:19 |
| Dec | 8.1 | 8:04 | 4:05 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Saint Helier averages about 7 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 4 and 12 days.
The sunnier stretch runs 4.7 months, from around May 6 to Sep 25. The sunniest month is July, with roughly 12 sunny days (mixed).
The greyest month is December, down near 4 sunny days — about 67% fewer than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 4 | 5 | 7 | 9 | 9 | 10 | 12 | 11 | 9 | 5 | 4 | 4 |
| Sky | Gloomy | Gloomy | Gloomy | Mixed | Mixed | Mixed | Mixed | Mixed | Mixed | Gloomy | Gloomy | Gloomy |
| Sunny days | Sky | |
|---|---|---|
| Jan | 4 | Gloomy |
| Feb | 5 | Gloomy |
| Mar | 7 | Gloomy |
| Apr | 9 | Mixed |
| May | 9 | Mixed |
| Jun | 10 | Mixed |
| Jul | 12 | Mixed |
| Aug | 11 | Mixed |
| Sep | 9 | Mixed |
| Oct | 5 | Gloomy |
| Nov | 4 | Gloomy |
| Dec | 4 | Gloomy |
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.
In Saint Helier, how humid it feels changes dramatically over the year.
The more humid part of the year lasts 3.2 months, from around June 26 to September 29. The muggiest month is August, when the air feels humid, muggy or worse about 27% of the time.
The most comfortable stretch runs from around September 30 to June 25, and May is the most comfortable month — the air is dry or comfortable 100% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 100 | 100 | 100 | 100 | 96 | 67 | 25 | 21 | 51 | 75 | 97 | 100 |
| Comfortable (%) | 0 | 0 | 0 | 0 | 4 | 31 | 60 | 52 | 38 | 24 | 3 | 0 |
| Humid (%) | 0 | 0 | 0 | 0 | 0 | 2 | 15 | 26 | 11 | 1 | 0 | 0 |
| Muggy (%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | |
|---|---|---|---|---|
| Jan | 100 | 0 | 0 | 0 |
| Feb | 100 | 0 | 0 | 0 |
| Mar | 100 | 0 | 0 | 0 |
| Apr | 100 | 0 | 0 | 0 |
| May | 96 | 4 | 0 | 0 |
| Jun | 67 | 31 | 2 | 0 |
| Jul | 25 | 60 | 15 | 0 |
| Aug | 21 | 52 | 26 | 1 |
| Sep | 51 | 38 | 11 | 0 |
| Oct | 75 | 24 | 1 | 0 |
| Nov | 97 | 3 | 0 | 0 |
| Dec | 100 | 0 | 0 | 0 |
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Across the year, average wind speed in Saint Helier is typically breezy, near 25 km/h, and varies a lot with the seasons.
The windier part of the year lasts 5.6 months, from around Oct 2 to Mar 19. The windiest month is January, averaging about 31 km/h (windy).
The calmer part of the year runs from around Mar 20 to Oct 1, with July the calmest month at about 21 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 31 | 29 | 26 | 23 | 22 | 21 | 21 | 21 | 24 | 27 | 30 | 31 |
| Feels | windy | breezy | breezy | breezy | breezy | breezy | breezy | breezy | breezy | breezy | windy | windy |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 31 | windy |
| Feb | 29 | breezy |
| Mar | 26 | breezy |
| Apr | 23 | breezy |
| May | 22 | breezy |
| Jun | 21 | breezy |
| Jul | 21 | breezy |
| Aug | 21 | breezy |
| Sep | 24 | breezy |
| Oct | 27 | breezy |
| Nov | 30 | windy |
| Dec | 31 | windy |
Hazard calendar for Saint Helier
When the seasonal hazards worth planning around — the rainy season, tropical-cyclone risk and dust haze — are active through the year.
Saint Helier's rainy season runs August–March, when most of the year's rain falls.
Best time to visit Saint Helier
To characterize how pleasant the weather is in Saint Helier throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around mid September, Saint Helier is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.
Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.
The travel score favors clear, rainless days with daytime highs between 18°C and 28°C. Based on this score, the best time of year to visit Saint Helier for general outdoor tourist activities is from mid June to late September, with a peak score in the last week of July.
The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Travel score (0–10) | 1.6 | 1.4 | 1.9 | 2.7 | 3.8 | 5.0 | 6.0 | 6.1 | 5.5 | 4.0 | 2.7 | 1.9 |
| Rating | poor | poor | poor | poor | fair | fair | good | good | fair | fair | poor | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 1.6 | poor |
| Feb | 1.4 | poor |
| Mar | 1.9 | poor |
| Apr | 2.7 | poor |
| May | 3.8 | fair |
| Jun | 5.0 | fair |
| Jul | 6.0 | good |
| Aug | 6.1 | good |
| Sep | 5.5 | fair |
| Oct | 4.0 | fair |
| Nov | 2.7 | poor |
| Dec | 1.9 | poor |
The beach/pool score favors clear, rainless days with daytime highs between 24°C and 34°C. Based on this score, the best time of year to visit Saint Helier for hot-weather activities is from mid July to early September, with a peak score in the first week of August.
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
What to pack for Saint Helier, by month
Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.
For a warm-season trip around August (highs near 18°C), the essentials are rain gear, sun protection and a windbreaker. In the cold season around February (highs near 9°C), pack a warm layer, rain gear and a windbreaker.
In August, Saint Helier sees daytime highs around 18°C and nights near 17°C. Worth packing: rain gear, sun protection and a windbreaker. About 10 days see rain.
Sea temperature near Saint Helier
Average ocean temperature at the nearest coast, month by month, banded into swim-comfort zones — the other half of the beach question.
The sea offshore is warmest in August at about 18°C and coldest in February near 9°C.
The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 10 | 9 | 9 | 10 | 12 | 15 | 17 | 18 | 18 | 16 | 14 | 11 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Cool | Cool | Cool | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 10 | Bracing |
| Feb | 9 | Bracing |
| Mar | 9 | Bracing |
| Apr | 10 | Bracing |
| May | 12 | Bracing |
| Jun | 15 | Bracing |
| Jul | 17 | Cool |
| Aug | 18 | Cool |
| Sep | 18 | Cool |
| Oct | 16 | Cool |
| Nov | 14 | Bracing |
| Dec | 11 | Bracing |
UV index (midday) in Saint Helier by month
Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.
Under clear skies, the midday UV index in Saint Helier peaks around August 13 at about 7 (high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 1 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 6 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 2 | 3 | 5 | 6 | 7 | 6 | 7 | 5 | 3 | 1 | 1 |
| Level | Low | Low | Moderate | Moderate | High | High | High | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Low |
| Mar | 3 | Moderate |
| Apr | 5 | Moderate |
| May | 6 | High |
| Jun | 7 | High |
| Jul | 6 | High |
| Aug | 7 | High |
| Sep | 5 | Moderate |
| Oct | 3 | Moderate |
| Nov | 1 | Low |
| Dec | 1 | Low |
Average hourly UV index in Saint Helier
Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.
The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
UV falls off far faster than brightness as the sun drops, so even in August the burn window is concentrated in the middle of the day: about 7 hours a day reach index 3 (protection recommended), and 2.5 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV ≥ 3 (h/day) | 0 | 0 | 0 | 5 | 7 | 7.5 | 7.5 | 7 | 5 | 0 | 0 | 0 |
| UV ≥ 6 (h/day) | 0 | 0 | 0 | 0 | 0 | 2.5 | 1 | 2.5 | 0 | 0 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 0 | 0 |
| Feb | 0 | 0 |
| Mar | 0 | 0 |
| Apr | 5 | 0 |
| May | 7 | 0 |
| Jun | 7.5 | 2.5 |
| Jul | 7.5 | 1 |
| Aug | 7 | 2.5 |
| Sep | 5 | 0 |
| Oct | 0 | 0 |
| Nov | 0 | 0 |
| Dec | 0 | 0 |
Growing season
Saint Helier is frost-free year round — even the coldest nights rarely reach freezing, so there is no start or end to the growing season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Frost nights | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 100 | 0 |
| Feb | 100 | 0 |
| Mar | 100 | 0 |
| Apr | 100 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 100 | 0 |
| Dec | 100 | 0 |
Growing degree days
Growing degree days tally heat above 10°C: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Saint Helier banks about 1,019 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°C·days) | 0 | 0 | 0 | 7 | 71 | 141 | 206 | 229 | 192 | 132 | 41 | 0 |
| Growing degree days (°C·days) | |
|---|---|
| Jan | 0 |
| Feb | 0 |
| Mar | 0 |
| Apr | 7 |
| May | 71 |
| Jun | 141 |
| Jul | 206 |
| Aug | 229 |
| Sep | 192 |
| Oct | 132 |
| Nov | 41 |
| Dec | 0 |
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
Saint Helier receives about 3.5 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 0.8 and 6.3 kWh/m².
The brighter stretch of the year lasts 5.9 months, from around Mar 23 to Sep 19. The brightest month is June, averaging about 6.2 kWh/m² (intense).
The dimmest month is December, down near 0.8 kWh/m² — roughly 86% less than the June peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 1.0 | 1.9 | 3.2 | 4.8 | 5.8 | 6.3 | 6.1 | 5.1 | 3.7 | 2.2 | 1.2 | 0.8 |
| Level | Dim | Dim | Moderate | Bright | Bright | Intense | Intense | Bright | Moderate | Moderate | Dim | Dim |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 1.0 | Dim |
| Feb | 1.9 | Dim |
| Mar | 3.2 | Moderate |
| Apr | 4.8 | Bright |
| May | 5.8 | Bright |
| Jun | 6.3 | Intense |
| Jul | 6.1 | Intense |
| Aug | 5.1 | Bright |
| Sep | 3.7 | Moderate |
| Oct | 2.2 | Moderate |
| Nov | 1.2 | Dim |
| Dec | 0.8 | Dim |
Where is Saint Helier?
Saint Helier sits at 49.2°N, 2.1°W, 11 m above sea level, in Jersey. The nearest listed city is Saint Peter Port, 43 km away.
Topography around Saint Helier
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Saint Helier.
Within 3 km, the terrain around Saint Helier has only modest variations in elevation — a maximum elevation change of 100 m around an average of 31 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 137 m; within 80 km, significant variations in elevation — a maximum elevation change of 290 m.
The land around Saint Helier is covered by water (32%), trees (22%) and artificial surfaces (21%) within 3 km, water (85%) within 16 km, and water (68%) within 80 km.
Jersey travel facts
- Power plugs
- Type G
- 230 V · 50 Hz
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Saint Helier (49.188°, -2.1049°, elevation 11 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).