Climate and Average Weather Year Round in Jersey Jersey

In Jersey, the summers are comfortable and windy; the winters are long, very cold, and extremely windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 40°F to 69°F and is rarely below 32°F or above 77°F.

Based on the tourism score, the best time of year to visit Jersey for warm-weather activities is from late June to mid September.

The warm season lasts for 3.1 months, from June 17 to September 21, with an average daily high temperature above 64°F. The hottest month of the year in Jersey is August, with an average high of 68°F and low of 58°F.

The cool season lasts for 3.9 months, from November 26 to March 22, with an average daily high temperature below 51°F. The coldest month of the year in Jersey is February, with an average low of 40°F and high of 47°F.

In Jersey, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Jersey begins around May 7 and lasts for 5.1 months, ending around October 11.

The clearest month of the year in Jersey is July, during which on average the sky is clear, mostly clear, or partly cloudy 60% of the time.

The cloudier part of the year begins around October 11 and lasts for 6.9 months, ending around May 7.

The cloudiest month of the year in Jersey is January, during which on average the sky is overcast or mostly cloudy 63% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Jersey varies throughout the year.

The wetter season lasts 5.5 months, from September 27 to March 13, with a greater than 27% chance of a given day being a wet day. The month with the most wet days in Jersey is December, with an average of 11.6 days with at least 0.04 inches of precipitation.

The drier season lasts 6.5 months, from March 13 to September 27. The month with the fewest wet days in Jersey is July, with an average of 5.5 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Jersey is December, with an average of 11.4 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 38% on November 23.

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Jersey experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in Jersey. The month with the most rain in Jersey is December, with an average rainfall of 2.8 inches.

The month with the least rain in Jersey is July, with an average rainfall of 1.1 inches.

The length of the day in Jersey varies extremely over the course of the year. In 2025, the shortest day is December 21, with 8 hours, 12 minutes of daylight; the longest day is June 21, with 16 hours, 14 minutes of daylight.

The earliest sunrise is at 5:02 AM on June 17, and the latest sunrise is 3 hours, 1 minute later at 8:03 AM on December 31. The earliest sunset is at 4:09 PM on December 11, and the latest sunset is 5 hours, 8 minutes later at 9:17 PM on June 25.

Daylight saving time (DST) is observed in Jersey during 2025, starting in the spring on March 30, lasting 6.9 months, and ending in the fall on October 26.

The figure below presents a compact representation of key lunar data for 2025. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in Jersey, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Jersey experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 5.9 months, from October 6 to April 4, with average wind speeds of more than 15.2 miles per hour. The windiest month of the year in Jersey is January, with an average hourly wind speed of 18.6 miles per hour.

The calmer time of year lasts for 6.1 months, from April 4 to October 6. The calmest month of the year in Jersey is July, with an average hourly wind speed of 11.8 miles per hour.

The predominant average hourly wind direction in Jersey is from the west throughout the year.

Jersey is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences some seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.2 months, from July 10 to October 17, with an average temperature above 60°F. The month of the year in Jersey with the warmest water is August, with an average temperature of 63°F.

The time of year with cooler water lasts for 3.8 months, from January 1 to April 26, with an average temperature below 51°F. The month of the year in Jersey with the coolest water is February, with an average temperature of 48°F.

To characterize how pleasant the weather is in Jersey throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Jersey for general outdoor tourist activities is from late June to mid September, with a peak score in the first week of August.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Jersey for hot-weather activities is from mid July to mid August, with a peak score in the first week of August.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Jersey typically lasts for 10 months (314 days), from around February 12 to around December 24, rarely starting after March 19, or ending before November 21.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Jersey should appear around May 3, only rarely appearing before April 17 or after May 23.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.3 months, from May 7 to August 17, with an average daily incident shortwave energy per square meter above 5.6 kWh. The brightest month of the year in Jersey is June, with an average of 6.7 kWh.

The darker period of the year lasts for 3.8 months, from October 26 to February 19, with an average daily incident shortwave energy per square meter below 2.0 kWh. The darkest month of the year in Jersey is December, with an average of 0.9 kWh.

For the purposes of this report, the geographical coordinates of Jersey are 49.217 deg latitude, -2.117 deg longitude, and 269 ft elevation.

The topography within 2 miles of Jersey contains only modest variations in elevation, with a maximum elevation change of 433 feet and an average elevation above sea level of 258 feet. Within 10 miles also contains only modest variations in elevation (459 feet). Within 50 miles contains only modest variations in elevation (978 feet).

The area within 2 miles of Jersey is covered by grassland (47%) and trees (39%), within 10 miles by water (92%), and within 50 miles by water (73%) and cropland (11%).