Saint Helier climate

Name: Saint Helier
Address: JE

Saint Helier is warmest in August, with average highs of 19 °C, and coldest in February, when nights average 6.2 °C. December is the wettest month (134 mm) and July the driest (49 mm). Figures are 1991–2020 climate normals.

Across a full year Saint Helier averages 995 mm of rain, 1 days above 25 °C and 1 days below freezing.

Jersey · population 28,000 · 1991–2020 normals

Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month

Warmest month August 19 °C
Coldest month February 6.2 °C
Driest month July 49 mm
Wettest month December 134 mm
Least cloud July 54 % cloud
Hottest on record July 31 °C
Coldest on record February -5.9 °C
Warmest sea August 18 °C

What to expectSaint Helier through the year

Saint Helier has a clear annual cycle: average daily highs run from 8.7 °C in February to 19 °C in August, a swing of 9.9 °C in mean temperature across the year.

Counted across a normal year, 1 days a year reach 25 °C, 0 of them reach 30 °C, 1 nights drop below freezing. The warmest reading in the 1991–2020 record is 31 °C, in July.

Rain is strongly seasonal. December averages 134 mm against 49 mm in July — 2.7 times as much. Planning around the dry months matters more here than planning around temperature.

The sea off Saint Helier is warmest in August at 18 °C and coldest in February at 8.7 °C. Sea temperature lags the air by a month or two, which is why late summer swims warmer than early summer at the same air temperature.

Month by month

Month	Avg high	Rainfall	Cloud
January	9.1 °C	108 mm	74 %
February	8.7 °C	80 mm	70 %
March	9.8 °C	69 mm	66 %
April	11.4 °C	57 mm	59 %
May	13.9 °C	54 mm	61 %
June	16.3 °C	53 mm	57 %
July	18.1 °C	49 mm	54 %
August	18.6 °C	65 mm	57 %
September	17.6 °C	74 mm	59 %
October	15.2 °C	119 mm	68 %
November	12.2 °C	131 mm	73 %
December	10.0 °C	134 mm	73 %

Temperature month by month

Month	Avg high	Avg low	Mean	Record high	Record low
January	9.1 °C	6.7 °C	7.9 °C	13.9 °C	-3.5 °C
February	8.7 °C	6.2 °C	7.5 °C	15.1 °C	-5.9 °C
March	9.8 °C	7.2 °C	8.5 °C	18.2 °C	-1.2 °C
April	11.4 °C	8.5 °C	10.0 °C	23.0 °C	1.0 °C
May	13.9 °C	10.9 °C	12.4 °C	25.0 °C	5.2 °C
June	16.3 °C	13.4 °C	14.8 °C	28.7 °C	7.8 °C
July	18.1 °C	15.4 °C	16.7 °C	31.0 °C	11.2 °C
August	18.6 °C	16.0 °C	17.4 °C	28.8 °C	12.1 °C
September	17.6 °C	15.0 °C	16.3 °C	26.8 °C	10.8 °C
October	15.2 °C	12.8 °C	14.0 °C	22.4 °C	5.2 °C
November	12.2 °C	10.0 °C	11.1 °C	17.7 °C	0.9 °C
December	10.0 °C	7.6 °C	8.9 °C	15.0 °C	-1.7 °C

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind	Sea temp
January	108 mm	15	8.7 h/day	74 %	79 %	40 km/h	9.5 °C
February	80 mm	13	10 h/day	70 %	78 %	37 km/h	8.7 °C
March	69 mm	13	12 h/day	66 %	79 %	34 km/h	8.7 °C
April	57 mm	11	14 h/day	59 %	79 %	31 km/h	10.1 °C
May	54 mm	10	15 h/day	61 %	80 %	29 km/h	12.0 °C
June	53 mm	9	16 h/day	57 %	82 %	28 km/h	14.5 °C
July	49 mm	9	16 h/day	54 %	82 %	27 km/h	16.6 °C
August	65 mm	10	14 h/day	57 %	81 %	28 km/h	17.9 °C
September	74 mm	11	13 h/day	59 %	78 %	30 km/h	17.5 °C
October	119 mm	15	11 h/day	68 %	77 %	35 km/h	15.9 °C
November	131 mm	17	9.1 h/day	73 %	78 %	38 km/h	13.5 °C
December	134 mm	17	8.2 h/day	73 %	78 %	39 km/h	11.2 °C

How Saint Helier compares

The same four figures for nearby destinations, so the numbers above have something to be read against. Summer high is the warmest month's average high; winter low is the coldest month's average low.

Destination	Summer high	Winter low	Rain per year	Days above 25 °C
Saint Helier	19 °C	6.2 °C	995 mm	1
Saint Peter Port · Guernsey	17 °C	7.1 °C	876 mm	0
Rennes · France	23 °C	2.8 °C	703 mm	26
Le Havre · France	22 °C	3.2 °C	931 mm	15
Bournemouth · United Kingdom	20 °C	4.0 °C	749 mm	4
Portsmouth · United Kingdom	21 °C	3.3 °C	714 mm	6
Southampton · United Kingdom	21 °C	3.0 °C	738 mm	6

Where Saint Helier ranks

Ranking	Position	Value
The coolest places in Europe in July	14thof 50	18 °C
The coolest places in Europe in June	19thof 50	16 °C
The coolest places in Europe in May	32ndof 50	14 °C
The coolest places in Europe in August	33rdof 50	19 °C
The coolest places in the world in May	46thof 50	14 °C

Planning a trip? See the best time to visit Saint Helier.

QuestionsCommon questions about Saint Helier’s climate

When is the best time to visit Saint Helier?

That depends on what you want, so the honest answer is a comparison rather than a single month. July, August, September sit closest to 20 °C on average, August is the warmest month and July the driest. The month-by-month table above has the full picture.

How hot does Saint Helier get?

In August, the warmest month, daily highs average 19 °C. About 0 days a year pass 30 °C. The highest value in the 1991–2020 record is 31 °C.

How cold does it get in winter?

Nights average 6.2 °C in February, the coldest month. A normal year has 1 nights below freezing.

Which month is wettest in Saint Helier?

December, averaging 134 mm over 17 days with rain. The driest month is July with 49 mm. The year as a whole averages 995 mm.

Are these figures a forecast?

No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in Saint Helier rather than what any particular week will bring. Individual years can differ substantially from the normal.

Data sources and method

ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
Open-Meteo — Open-Meteo.com. CC BY 4.0
NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
GeoNames — GeoNames.org. CC BY 4.0

Normal period: 1991–2020
Dataset version: era5-1991-2020-scores1.1
Last processed: 1 August 2026

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.