Dorchester weather in September

In September, Dorchester sees average daytime highs of 18°C and overnight lows near 11°C, with 56 mm of rain across 9.3 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 19°C in the first days to 17°C by the end. The sky is clear or mostly clear about 16% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 24 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Dorchester's 4th-clearest and 9th-windiest month. For the whole year in context, see Dorchester's year-round climate.

Daytime high
18°
4th warmest
Overnight low
11°
9th coldest
Rainfall
56 mm
9.3 wet days
Daylight
12 h 24 min
5:53 AM – 6:15 PM
Cloud cover
68%
4th clearest
Wind
15 km/h
9th windiest
Solar energy
3.24 kWh/m²
Travel score
5.7
out of 10

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.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 19°C in the first days to 17°C by the end.

A typical September day in Dorchester reaches about 18°C in the afternoon and slips back to 11°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 21°C. Set against its neighbours, September runs about 2°C cooler than August and about 4°C warmer than October.

10°15°20°25°151015202530
Avg high (°C)Avg low (°C)
11912
21912
31912
41912
51912
61912
71912
81912
91912
101912
111812
121811
131811
141811
151811
161811
171811
181811
191811
201811
211711
221711
231711
241711
251711
261711
271710
281710
291610
301610

How September really feels in Dorchester

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Dorchester weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 11th-wettest month here — the current month is highlighted below.

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

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 16% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 66%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13565
23565
33565
43565
53565
63466
73565
83565
93565
103565
113466
123466
133466
143466
153565
163565
173565
183565
193565
203466
213466
223565
233565
243565
253466
263466
273565
283466
293466
303466

Chance of precipitation in September

Any precipitation

Dorchester gets around 56 mm of rain over 9.3 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 31% and peaks near 39% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
128
227
327
427
527
627
727
828
928
1028
1128
1229
1329
1429
1530
1630
1730
1831
1931
2032
2133
2233
2334
2435
2536
2636
2737
2838
2938
3039

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 68% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
156386
257376
358366
459356
560346
662326
762317
863307
965296
1066286
1167276
1268266
1369265
1470255
1570255
1671254
1771254
1871263
1971263
2072262
2171272
2271272
2371272
2472271
2572271
2672271
2773261
2874251
2975241
3076231

Wind in September

Winds average 15 km/h in September.

Across September, daily wind ranges from about 14 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
114light breeze
214light breeze
314light breeze
414light breeze
514light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2916light breeze
3016light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 24 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 114 minutes over September. Sunrise moves from 5:29 AM to 6:15 AM, and sunset from 6:50 PM to 5:43 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.45:296:50
213.35:306:48
313.25:326:45
413.25:346:43
513.15:356:41
613.05:376:39
713.05:386:36
812.95:406:34
912.85:426:32
1012.85:436:29
1112.75:456:27
1212.65:466:25
1312.65:486:22
1412.55:506:20
1512.45:516:18
1612.45:536:15
1712.35:546:13
1812.25:566:11
1912.25:586:08
2012.15:596:06
2112.06:016:04
2212.06:026:01
2311.96:045:59
2411.96:065:57
2511.86:075:54
2611.76:095:52
2711.76:105:50
2811.66:125:47
2911.56:145:45
3011.56:155:43

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.24 kWh/m².

For context, solar energy here swings from a low near 0.71 kWh/m² to a high of 5.56 kWh/m² in June across the year — September's 3.24 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.9Moderate
23.8Moderate
33.8Moderate
43.8Moderate
53.7Moderate
63.7Moderate
73.6Moderate
83.6Moderate
93.5Moderate
103.5Moderate
113.5Moderate
123.4Moderate
133.4Moderate
143.3Moderate
153.3Moderate
163.2Moderate
173.2Moderate
183.1Moderate
193.1Moderate
203.0Moderate
213.0Moderate
222.9Moderate
232.9Moderate
242.8Moderate
252.8Moderate
262.7Moderate
272.7Moderate
282.6Moderate
292.6Moderate
302.5Moderate
Planning a trip in September

Is September a good time to visit Dorchester?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

5.7
Sightseeing
3rd-best month of the year
1.9
Beach & pool
4th-best month of the year

September is a reasonable time to visit Dorchester for sightseeing.

What to pack for Dorchester in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Dorchester sees daytime highs around 18°C and nights near 11°C. Worth packing: rain gear. About 9 days see rain.

rain gear

Sea temperature near Dorchester in September

The nearest coast averages about 17°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

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 in Dorchester in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

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
Location & terrain

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
September weather 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).