Dover weather in September

In September, Dover sees average daytime highs of 74°F and overnight lows near 56°F, with 4.5 in of rain across 9.5 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 1st-wettest month of the year here.

Highs ease over the month, from about 78°F in the first days to 70°F by the end. The sky is clear or mostly clear about 34% 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 2nd-clearest and 9th-windiest month. For the whole year in context, see Dover's year-round climate.

Daytime high
74°
4th warmest
Overnight low
56°
9th coldest
Rainfall
4.5 in
9.5 wet days
Daylight
12 h 18 min
5:45 AM – 6:01 PM
Cloud cover
56%
2nd clearest
Wind
6 mph
9th windiest
Solar energy
4.17 kWh/m²
Travel score
6.9
out of 10

Dover is town in Morris County, New Jersey, United States.

Density
2,595/km²
people per km²
Founded
1869

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 78°F in the first days to 70°F by the end.

A typical September day in Dover reaches about 74°F in the afternoon and slips back to 56°F overnight — a 18°F spread between the day's warmth and the night's chill. On most days the high lands between 65°F and 83°F. Set against its neighbours, September runs about 7°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17961
27961
37861
47861
57860
67860
77760
87759
97759
107659
117658
127658
137558
147557
157457
167456
177456
187356
197355
207355
217255
227254
237154
247153
257153
267053
277052
286952
296952
306951

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 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan36° / 22°3.59.35.59.40.0
Feb39° / 23°3.08.74.510.40.0
Mar47° / 31°4.310.94.111.71.5
Apr59° / 41°3.8110.813.14.4
May69° / 51°3.911.9014.36.1
Jun78° / 60°4.211.4014.96.4
Jul83° / 65°4.210.8014.65.6
Aug81° / 64°4.010.4013.66.3
Sep74° / 56°4.59.5012.36.9
Oct62° / 45°4.18.90.210.95.5
Nov51° / 35°3.38.30.99.72.5
Dec41° / 28°4.19.73.99.10.2

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 50%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14951
24951
35050
44951
54951
64951
75050
85050
95149
105149
115149
125248
135248
145248
155248
165248
175248
185149
195248
205149
215050
225050
235050
244951
254951
264951
275050
285050
295050
305149

Chance of precipitation in September

Any precipitation

Dover gets around 4.5 in of rain over 9.5 wet days in September, the wettest month. 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 32% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
127
227
328
428
529
629
729
830
930
1030
1131
1231
1331
1431
1531
1631
1731
1831
1931
2031
2132
2232
2332
2432
2532
2632
2732
2832
2932
3032

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 49% of days. Sticky, muggy-or-worse air turns up on roughly 13% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1322423165
2322323165
3332322165
4342322165
5352321155
6362321155
7372320155
8392319144
9392319144
10412318144
11422318143
12432318133
13442217133
14462217122
15472117122
16492117112
17502017112
18531917101
19531917101
2055181791
2156171791
2258161781
2361151680
2463141670
2564141660
2666131560
2767131550
2867131550
2969121450
3070121440

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

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 5:29 AM to 5:59 AM, and sunset from 6:27 PM to 5:36 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:296:27
212.95:306:25
312.95:316:23
412.85:326:22
512.85:336:20
612.75:346:18
712.75:356:16
812.65:366:15
912.65:376:13
1012.55:386:11
1112.55:396:09
1212.55:406:08
1312.45:416:06
1412.45:436:04
1512.35:446:02
1612.35:456:01
1712.25:465:59
1812.25:475:57
1912.15:485:55
2012.15:495:54
2112.05:505:52
2212.05:515:50
2311.95:525:48
2411.95:535:46
2511.85:545:45
2611.85:555:43
2711.85:565:41
2811.75:575:40
2911.75:585:38
3011.65:595:36

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.17 kWh/m².

For context, solar energy here swings from a low near 1.72 kWh/m² to a high of 5.95 kWh/m² in June across the year — September's 4.17 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.7Bright
34.7Bright
44.6Bright
54.6Bright
64.5Bright
74.5Bright
84.5Bright
94.4Bright
104.4Bright
114.4Bright
124.3Bright
134.3Bright
144.3Bright
154.2Bright
164.2Bright
174.1Bright
184.1Bright
194.1Bright
204.0Bright
214.0Moderate
223.9Moderate
233.9Moderate
243.9Moderate
253.8Moderate
263.8Moderate
273.7Moderate
283.7Moderate
293.6Moderate
303.6Moderate
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
5.4
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 74°F and nights near 56°F. Worth packing: light clothes and rain gear. About 10 days see rain.

light clothesrain gear

Sea temperature near Dover in September

The nearest coast averages about 71°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 40 mi away) is warmest in August at about 74°F and coldest in February near 40°F.

It's comfortable for a long swim from Jun 30 to Sep 26 — about 2.9 months when the water holds above 68°F.

40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan43Bracing
Feb40Bracing
Mar41Bracing
Apr46Bracing
May55Bracing
Jun65Cool
Jul72Refreshing
Aug74Refreshing
Sep71Refreshing
Oct63Cool
Nov55Bracing
Dec48Bracing

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 11 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 22 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 11UV 8Dec 22UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Dover in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Dover is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (November, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1317 µg/m³Nov 159 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar14Moderate
Apr14Moderate
May16Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep13Moderate
Oct10Good
Nov9Good
Dec10Good
Location & terrain

Where is Dover?

Dover sits at 40.9°N, 74.6°W, 577 ft above sea level, in United States. The nearest listed city is Randolph, 2.5 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 525 ft around an average of 738 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,266 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,467 ft.

The land around Dover is covered by trees (68%) and artificial surfaces (25%) within 2 miles, trees (82%) within 10 miles, and trees (70%) within 50 miles.

2 miles
525 ft
10 miles
1,266 ft
50 miles
2,467 ft
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Randolph 2.5 mi · Denville 4.3 mi · Hopatcong Hills 6.8 mi · Parsippany 7.5 mi · Morristown 7.5 mi · Sparta 11 mi · Madison 11 mi · Basking Ridge 12 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 (40.884°, -74.5621°, elevation 577 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. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).