Climate and average weather in Dorchester

In Dorchester, the summers are mild, showery, and partly cloudy and the winters are cold and mostly cloudy.

Best: late May to late September

Over the course of the year, the temperature in Dorchester typically varies from 3°C to 20°C, and is rarely below -2°C or above 25°C. July is the hottest month of the year, while January is the coldest.

Based on the travel score, the best time of year to visit Dorchester for warm-weather activities is from late May to late September.

Hottest
Jul
20°
Coldest
Jan
Wettest
Oct
81 mm
Driest
Mar
53 mm
Rain / yr
781 mm
133 wet days
Daylight
7.7–16.3 h
shortest–longest
Elevation
55 m
50.7°N
Clearest
Jul
67% cloud

Dorchester is town in Dorset, England, UK.

Density
3,431/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Dorchester 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 late May to late September.

Temperature through the year

Average highAverage lowShaded bands: 10–90% of days

Daily average highs and lows in Dorchester, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.

The hot season lasts 3.5 months, from June 6 to September 19, with daily high temperatures above 18°C. The hottest month of the year in Dorchester is July, with an average high of 20°C and low of 13°C.

The cool season lasts 3.8 months, from November 21 to March 16, with daily high temperatures below 10°C. The coldest month of the year in Dorchester is January, with an average low of 4°C and high of 8°C.

Days typically run about 6°C warmer than nights year-round.

10°20°30°JanFebMarAprMayJunJulAugSepOctNovDec
Avg high (°C)Avg low (°C)
Jan84
Feb83
Mar104
Apr136
May169
Jun1811
Jul2013
Aug2013
Sep1811
Oct149
Nov116
Dec94

How hot and cold Dorchester really feels

Feels-like highFeels-like lowactual air temp

The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.

On the coldest nights, wind chill pulls the feels-like down to about -1°C (around January 28), with roughly 78 freezing days a year (feels-like at or below 0°C), worst in January.

-5°10°15°20°25°JanFebMarAprMayJunJulAugSepOctNovDec
Feels-like high (°C)Air high (°C)Feels-like low (°C)Air low (°C)
Jan88-14
Feb88-13
Mar101014
Apr131336
May161669
Jun18181111
Jul20201313
Aug20201313
Sep18181111
Oct141469
Nov111136
Dec9904

Average hourly temperature in Dorchester

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 July afternoons, near 20°C, and coldest before dawn in January, near C.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM

Dorchester weather by month

Every month at a glance. Click a month for its detailed page.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 70120.38.31.2
Feb / 5610.50.69.71.3
Mar10° / 5310.10.411.52.3
Apr13° / 6311.50.113.53.3
May16° / 6311.1015.24.6
Jun18° / 11°6010.8016.25.7
Jul20° / 13°5710.8015.86.2
Aug20° / 13°7110.7014.36.1
Sep18° / 11°569.3012.45.7
Oct14° / 8112.3010.43.9
Nov11° / 7712.208.72.4
Dec / 7611.70.27.81.5

Chance of rain

How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.

Dorchester gets about 781 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 2.2 months, from around Sep 27 to Dec 2, peaking in October at about 42% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Sep 6.

October is the wettest month by volume, with 81 mm over about 12 wet days; March is the driest, with 53 mm.

0%10%20%30%40%50%JanFebMarAprMayJunJulAugSepOctNovDecdrierwetterdriermostly drysome rainoften wetvery wetOct 30 · 42%Sep 6 · 28%
Rain on a day (%)Rain days
Jan3912
Feb3711
Mar3310
Apr3712
May3711
Jun3611
Jul3411
Aug3411
Sep319
Oct3912
Nov4012
Dec3912

Monthly rainfall

Over a full year, Dorchester collects about 781 mm of rain across 133 wet days — roughly 65 mm in an average month.

It doesn’t fall evenly. October is the wettest month with 81 mm, while March is the driest at just 53 mm. The three wettest months alone bring about 30% of the year’s total, and some of the cold-season precipitation falls as snow.

0255075100JanFebMarAprMayJunJulAugSepOctNovDec705653636360577156817776
Rainfall (mm)Rain daysSnow days
Jan70120
Feb56111
Mar53100
Apr63120
May63110
Jun60110
Jul57110
Aug71110
Sep5690
Oct81120
Nov77120
Dec76120

Clouds and sunshine

ClearMostly clearPartly cloudyMostly cloudyOvercast

How often the daytime sky is clear, partly cloudy or overcast.

In Dorchester, the average share of the sky covered by clouds shows mild seasonal variation over the course of the year.

The clearer part of the year begins around June 23 and lasts for 3.5 months, ending around October 6. The clearest month is July, when the sky is clear, mostly clear, or partly cloudy 37% of the time on average.

The cloudier part of the year begins around October 22 and lasts for 5.0 months, ending around March 23. The cloudiest month is February, when it is overcast or mostly cloudy 72% of the time.

0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%JanFebMarAprMayJunJulAugSepOctNovDecJul 22 · 40%Jan 31 · 27%clearmostly clearpartly cloudymostly cloudyovercastcloudierclearercloudier
Clearer (%)Cloudier (%)
Jan2971
Feb2872
Mar3070
Apr3763
May3268
Jun3268
Jul3763
Aug3664
Sep3466
Oct3268
Nov3070
Dec2971

Daylight, sunrise and sunset

DaylightNight

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 18, brings about 16 h 18 min of light; the shortest, around December 18, only 7 h 42 min — a swing of roughly 8 h 36 min.

12 AM4 AM8 AM12 PM4 PM8 PM12 AMJanFebMarAprMayJunJulAugSepOctNovDec
Daylight (h)Sunrise (AM)Sunset (PM)
Jan8.38:134:25
Feb9.77:345:15
Mar11.56:346:05
Apr13.55:246:56
May15.24:287:44
Jun16.24:038:17
Jul15.84:208:11
Aug14.35:047:24
Sep12.45:536:15
Oct10.46:425:08
Nov8.77:354:15
Dec7.88:133:59

Sunny days

How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.

Dorchester gets about 5 sunny days a month gloomy — and it barely shifts through the year, holding between 4 and 6 days every month. Clear skies here are a flat line, not a season.

0510JanFebMarAprMayJunJulAugSepOctNovDecgloomymixedApr 126 daysJun 104 days
Sunny daysSky
Jan5Gloomy
Feb4Gloomy
Mar5Gloomy
Apr6Gloomy
May5Gloomy
Jun5Gloomy
Jul6Gloomy
Aug5Gloomy
Sep5Gloomy
Oct5Gloomy
Nov5Gloomy
Dec5Gloomy

Humidity comfort

DryComfortableHumidMuggyOppressiveMiserable

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 Dorchester, the air stays dry or comfortable essentially all year. Even in August, the muggiest month, it feels humid or worse only about 13% of the time — humidity is not something you need to plan around here.

0%10%20%30%40%50%60%70%80%90%100%JanFebMarAprMayJunJulAugSepOctNovDecApr 25 · 100%Aug 9 · 84%humidcomfortabledrycomfortablehumidcomfortable
Dry (%)Comfortable (%)Humid (%)Muggy (%)
Jan100000
Feb100000
Mar100000
Apr100000
May95500
Jun762220
Jul454690
Aug4344121
Sep682840
Oct861400
Nov98200
Dec100000

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 Dorchester is typically light breeze, near 16 km/h, and varies little with the seasons.

The windier part of the year lasts 5.7 months, from around Oct 8 to Mar 31. The windiest month is January, averaging about 18 km/h (light breeze).

The calmer part of the year runs from around Apr 1 to Oct 7, with July the calmest month at about 14 km/h.

0510152025JanFebMarAprMayJunJulAugSepOctNovDecwindiercalmerwindiercalmlight breezebreezyJan 8 · 19 km/hJul 27 · 14 km/h
Wind speed (km/h)Feels
Jan18light breeze
Feb18light breeze
Mar17light breeze
Apr15light breeze
May15light breeze
Jun14light breeze
Jul14light breeze
Aug14light breeze
Sep15light breeze
Oct17light breeze
Nov17light breeze
Dec18light breeze

Best time to visit Dorchester

TravelBeach/poolTemperatureCloudsPrecipitation

To characterize how pleasant the weather is in Dorchester throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.

Around mid September, Dorchester 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 Dorchester for general outdoor tourist activities is from late May to late September, with a peak score in the third week of July.

0246810JanFebMarAprMayJunJulAugSepOctNovDecbest timetravel scoretemperaturecloudsprecipitationJul 21 · 6.3

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).

Travel score (0–10)Rating
Jan1.2poor
Feb1.3poor
Mar2.3poor
Apr3.4poor
May4.6fair
Jun5.7good
Jul6.2good
Aug6.1good
Sep5.7good
Oct3.9fair
Nov2.4poor
Dec1.5poor

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 Dorchester for hot-weather activities is from early July to late August, with a peak score in the last week of July.

024681012JanFebMarAprMayJunJulAugSepOctNovDecbest timebeach/pool scoretemperaturecloudsprecipitationJul 26 · 3.8

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 Dorchester, by month

EssentialRecommendedOptional

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 July (highs near 20°C), the essentials are rain gear and sun protection. In the cold season around January (highs near 8°C), pack a warm layer, a heavy coat and rain gear.

Light clothing
Warm layer
Winter coat
Rain gear
Sun protection
Windbreaker

In July, Dorchester sees daytime highs around 20°C and nights near 13°C. Worth packing: rain gear and sun protection. About 11 days see rain.

Sea temperature near Dorchester

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 17°C and coldest in March near 8°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan10Bracing
Feb9Bracing
Mar8Bracing
Apr10Bracing
May11Bracing
Jun14Bracing
Jul16Cool
Aug17Cool
Sep17Cool
Oct16Cool
Nov13Bracing
Dec11Bracing

UV index (midday) in Dorchester by month

LowModerateHighVery highExtreme

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 Dorchester peaks around August 13 at about 6 (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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowAug 13UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr4Moderate
May6High
Jun6High
Jul6High
Aug7High
Sep4Moderate
Oct2Moderate
Nov1Low
Dec1Low

Average hourly UV index in Dorchester

LowModerateHighVery highExtreme

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 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.

JanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM
UV ≥ 3 (h/day)UV ≥ 6 (h/day)
Jan00
Feb00
Mar00
Apr4.50
May6.50
Jun7.51
Jul70
Aug72
Sep4.50
Oct00
Nov00
Dec00
Almanac & agriculture

Growing season

Chance of a frost-free dayReliably frost-free (≥90%)

Dorchester is mild enough that a frost-free day stays more likely than not even in midwinter. Nights are reliably above freezing from about March 9 to November 27 (264 days); outside that window a hard frost is an occasional risk.

0%25%50%75%100%JanFebMarAprMayJunJulAugSepOctNovDecreliably frost-freeMar 990%Nov 2790%
Frost-free chance (%)Frost nights
Jan8431
Feb8228
Mar929
Apr980
May1000
Jun1000
Jul1000
Aug1000
Sep1000
Oct990
Nov946
Dec8631

Growing degree days

Degree days (base 10°C)Frost-free shaded

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. Dorchester banks about 819 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around July.

02004006008001,000JanFebMarAprMayJunJulAugSepOctNovDec
Growing degree days (°C·days)
Jan0
Feb0
Mar0
Apr2
May66
Jun146
Jul212
Aug208
Sep136
Oct50
Nov0
Dec0

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.

Dorchester receives about 3.1 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 0.7 and 5.6 kWh/m².

The brighter stretch of the year lasts 5.9 months, from around Mar 23 to Sep 18. The brightest month is June, averaging about 5.5 kWh/m² (bright).

The dimmest month is December, down near 0.7 kWh/m² — roughly 87% less than the June peak.

01234567JanFebMarAprMayJunJulAugSepOctNovDecdimmerbrighterdimmerdimmoderatebrightintenseJun 225.6 kWhDec 220.7 kWh
Solar energy (kWh/m²)Level
Jan0.9Dim
Feb1.6Dim
Mar2.8Moderate
Apr4.4Bright
May5.3Bright
Jun5.6Bright
Jul5.3Bright
Aug4.4Bright
Sep3.2Moderate
Oct1.9Dim
Nov1.1Dim
Dec0.7Dim

Where is Dorchester?

Dorchester sits at 50.7°N, 2.4°W, 55 m above sea level, in United Kingdom. The nearest listed city is Weymouth, 12 km away.

Topography around Dorchester

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Dorchester.

Within 3 km, the terrain around Dorchester has only modest variations in elevation — a maximum elevation change of 75 m around an average of 74 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 272 m; within 80 km, significant variations in elevation — a maximum elevation change of 408 m.

The land around Dorchester is covered by grassland (42%) and cropland (30%) within 3 km, grassland (42%) and cropland (27%) within 16 km, and grassland (36%) and water (35%) within 80 km.

3 km
75 m
16 km
272 m
80 km
408 m
treesgrasslandcroplandartificial surfaceswater
Nearby: Weymouth 12 km · Yeovil 29 km · Poole 32 km · Wimborne Minster 33 km · Ferndown 39 km · Bournemouth 39 km · Christchurch 46 km · New Milton 54 km

United Kingdom travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G / M
230 V · 50 Hz
Prices
≈ 89% of US
price level, 2025
GDP per capita
$57,602
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1.1
per 100k, 2021
Road deaths
3.2
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 60%none 26%Muslim 4%other 2%

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 Dorchester (50.7167°, -2.4333°, elevation 55 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).