Dover weather in September

In September, Dover sees average daytime highs of 71°F and overnight lows near 55°F, with 3.4 in of rain across 8.3 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 8th-wettest month of the year here.

Highs ease over the month, from about 75°F in the first days to 66°F by the end. The sky is clear or mostly clear about 38% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Dover's 1st-clearest and 9th-windiest month. For the whole year in context, see Dover's year-round climate.

Daytime high
71°
4th warmest
Overnight low
55°
9th coldest
Rainfall
3.4 in
8.3 wet days
Daylight
12 h 18 min
5:29 AM – 5:47 PM
Cloud cover
54%
1st clearest
Wind
7 mph
9th windiest
Solar energy
4.22 kWh/m²
Travel score
6.9
out of 10

Dover is county seat city in Strafford County, New Hampshire, United States.

Density
411/km²
people per km²
Founded
1623

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 75°F in the first days to 66°F by the end.

A typical September day in Dover reaches about 71°F in the afternoon and slips back to 55°F overnight — a 16°F spread between the day's warmth and the night's chill. On most days the high lands between 62°F and 80°F. Set against its neighbours, September runs about 7°F cooler than August and about 11°F warmer than October.

40°50°60°70°80°151015202530
Avg high (°F)Avg low (°F)
17560
27559
37559
47559
57458
67458
77458
87358
97357
107357
117257
127256
137256
147156
157155
167155
177055
187054
197054
206954
216953
226953
236853
246852
256752
266752
276751
286651
296651
306550

How September really feels in Dover

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
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.

Dover weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 8th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan32° / 19°3.49.36.89.20.0
Feb34° / 20°3.296.110.20.0
Mar42° / 28°4.210.95.411.60.4
Apr54° / 38°4.010.51.413.13.1
May64° / 48°3.010.3014.45.5
Jun74° / 58°3.610.8015.16.5
Jul79° / 64°3.210.7014.96.5
Aug78° / 62°3.39.2013.86.9
Sep71° / 55°3.48.3012.36.9
Oct59° / 45°4.29.50.210.84.8
Nov48° / 35°3.69.21.29.51.8
Dec38° / 26°4.410.45.28.90.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 46%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15842
25743
35644
45644
55545
65446
75446
85446
95446
105446
115446
125446
135446
145446
155347
165347
175347
185347
195446
205347
215347
225347
235248
245248
255248
265248
275248
285248
295248
305248

Chance of precipitation in September

Any precipitation

Dover gets around 3.4 in of rain over 8.3 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 28% and peaks near 29% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
125
225
326
426
527
627
728
828
929
1029
1129
1229
1328
1428
1528
1628
1727
1827
1927
2027
2127
2227
2327
2427
2527
2628
2728
2828
2929
3029

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 50% of days. Sticky, muggy-or-worse air turns up on roughly 9% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1312823162
2322823152
3342822152
4352822141
5362822131
6372722131
7382721121
8402721121
9412621111
10422620111
11432620101
12452520101
13462519100
1447251890
1549241890
1651241780
1751241780
1853231770
1954231670
2055221670
2157221560
2259211460
2360211450
2462201350
2564201240
2665201140
2767191040
286919930
297018930
307217830

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 7 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
227calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 5:12 AM to 5:45 AM, and sunset from 6:14 PM to 5:20 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:126:14
213.05:136:12
312.95:146:11
412.95:166:09
512.85:176:07
612.85:186:05
712.75:196:03
812.75:206:02
912.65:216:00
1012.65:225:58
1112.55:235:56
1212.55:255:54
1312.45:265:52
1412.45:275:50
1512.35:285:48
1612.35:295:47
1712.25:305:45
1812.25:315:43
1912.15:335:41
2012.15:345:39
2112.05:355:37
2212.05:365:35
2311.95:375:33
2411.95:385:31
2511.85:395:30
2611.85:415:28
2711.75:425:26
2811.75:435:24
2911.65:445:22
3011.65:455:20

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.22 kWh/m².

For context, solar energy here swings from a low near 1.54 kWh/m² to a high of 6.07 kWh/m² in July across the year — September's 4.22 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.9Bright
34.8Bright
44.8Bright
54.7Bright
64.7Bright
74.6Bright
84.6Bright
94.5Bright
104.5Bright
114.4Bright
124.4Bright
134.3Bright
144.3Bright
154.3Bright
164.2Bright
174.2Bright
184.1Bright
194.1Bright
204.0Bright
214.0Moderate
223.9Moderate
233.9Moderate
243.8Moderate
253.8Moderate
263.7Moderate
273.7Moderate
283.6Moderate
293.6Moderate
303.5Moderate
Planning a trip in September

Hazard calendar for Dover

In seasonPeak

In September, Dover sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Dover sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Dover?

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

6.9
Sightseeing
1st-best month of the year
4.5
Beach & pool
4th-best month of the year

September is a reasonable time to visit Dover for sightseeing.

What to pack for Dover in September

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

In September, Dover sees daytime highs around 71°F and nights near 55°F. Worth packing: rain gear. About 8 days see rain.

rain gear

Sea temperature near Dover in September

The nearest coast averages about 62°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 14 mi away) is warmest in August at about 65°F and coldest in March near 38°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

40°50°60°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°F)Comfort
Jan42Bracing
Feb39Bracing
Mar38Bracing
Apr42Bracing
May49Bracing
Jun57Bracing
Jul63Cool
Aug65Cool
Sep62Cool
Oct55Bracing
Nov49Bracing
Dec45Bracing

UV index in Dover in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Dover peaks around July 10 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 23 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighHighModerateModerateLowJul 10UV 7Dec 23UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May7High
Jun7High
Jul7Very high
Aug4Moderate
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low
Location & terrain

Where is Dover?

Dover sits at 43.2°N, 70.9°W, 62 ft above sea level, in United States. The nearest listed city is Rochester, 8.7 mi away.

Topography around Dover

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Dover.

Within 2 miles, the terrain around Dover has only modest variations in elevation — a maximum elevation change of 315 ft around an average of 121 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 696 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,943 ft.

The land around Dover is covered by trees (62%) and grassland (20%) within 2 miles, trees (75%) within 10 miles, and trees (67%) and water (27%) within 50 miles.

2 miles
315 ft
10 miles
696 ft
50 miles
2,943 ft
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Rochester 8.7 mi · Portsmouth 9.9 mi · Sanford 17 mi · Amesbury 24 mi · Newburyport 27 mi · Biddeford 29 mi · Saco 30 mi · Derry Village 30 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 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 Dover (43.1979°, -70.8737°, elevation 62 ft), 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).