Brunswick weather in September

In September, Brunswick sees average daytime highs of 69°F and overnight lows near 54°F, with 3.4 in of rain across 8.6 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 73°F in the first days to 64°F by the end. The sky is clear or mostly clear about 37% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Brunswick's 1st-clearest and 9th-windiest month. For the whole year in context, see Brunswick's year-round climate.

Daytime high
69°
4th warmest
Overnight low
54°
9th coldest
Rainfall
3.4 in
8.6 wet days
Daylight
12 h 18 min
5:25 AM – 5:43 PM
Cloud cover
54%
1st clearest
Wind
7 mph
9th windiest
Solar energy
4.18 kWh/m²
Travel score
6.6
out of 10

Brunswick is town in Cumberland County, Maine, United States.

Founded
1628

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 73°F in the first days to 64°F by the end.

A typical September day in Brunswick reaches about 69°F in the afternoon and slips back to 54°F overnight — a 15°F spread between the day's warmth and the night's chill. On most days the high lands between 61°F and 77°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)
17458
27358
37358
47357
57357
67257
77256
87256
97156
107156
117155
127055
137055
146954
156954
166954
176953
186853
196853
206752
216752
226752
236651
246651
256551
266550
276550
286450
296449
306449

How September really feels in Brunswick

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.

Brunswick weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan30° / 15°3.39.26.89.10.0
Feb32° / 16°3.08.76.610.20.0
Mar40° / 25°3.910.25.911.60.2
Apr51° / 37°3.810.72.113.22.6
May62° / 46°3.110.60.114.55.1
Jun71° / 56°3.610.7015.26.4
Jul77° / 62°3.19.9014.96.8
Aug76° / 61°3.18.7013.87.2
Sep69° / 54°3.48.6012.36.6
Oct57° / 44°4.59.90.210.84.2
Nov46° / 33°3.69.51.89.51.2
Dec36° / 22°4.1116.28.80.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 47%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15743
25743
35644
45545
55545
65545
75545
85446
95446
105446
115446
125446
135347
145446
155446
165347
175446
185347
195248
205248
215149
225149
235149
245050
255149
265149
275149
285149
295149
305149

Chance of precipitation in September

Any precipitation

Brunswick gets around 3.4 in of rain over 8.6 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 29% and peaks near 30% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
125
225
326
426
527
627
728
829
929
1029
1130
1230
1330
1430
1530
1630
1730
1830
1929
2029
2129
2229
2329
2429
2529
2630
2730
2830
2930
3030

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 55% of days. Sticky, muggy-or-worse air turns up on roughly 5% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1352923121
2372823121
3382822111
4392822100
5402821100
642282190
743282190
844272080
945272080
1047272070
1148261970
1249261960
1351251860
1452251850
1554241750
1656241640
1756241640
1857241540
1959231530
2060231430
2161221430
2262221330
2365211220
2466211120
2567201120
2669191020
277119910
287318810
297517710
307616710

Wind in September

Winds average 7 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
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 h 06 min 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 90 minutes over September. Sunrise moves from 5:08 AM to 5:42 AM, and sunset from 6:11 PM to 5:16 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:086:11
213.05:096:10
313.05:106:08
412.95:116:06
512.95:126:04
612.85:146:02
712.85:156:00
812.75:165:58
912.75:175:57
1012.65:185:55
1112.65:195:53
1212.55:215:51
1312.55:225:49
1412.45:235:47
1512.35:245:45
1612.35:255:43
1712.25:265:41
1812.25:285:39
1912.15:295:37
2012.15:305:35
2112.05:315:33
2212.05:325:32
2311.95:345:30
2411.95:355:28
2511.85:365:26
2611.85:375:24
2711.75:385:22
2811.75:405:20
2911.65:415:18
3011.65:425:16

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.18 kWh/m².

For context, solar energy here swings from a low near 1.48 kWh/m² to a high of 5.99 kWh/m² in July across the year — September's 4.18 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.9Bright
24.8Bright
34.8Bright
44.8Bright
54.7Bright
64.7Bright
74.6Bright
84.5Bright
94.5Bright
104.5Bright
114.4Bright
124.4Bright
134.3Bright
144.3Bright
154.2Bright
164.2Bright
174.1Bright
184.1Bright
194.0Bright
204.0Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.8Moderate
253.7Moderate
263.7Moderate
273.6Moderate
283.6Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Hazard calendar for Brunswick

In seasonPeak

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

Brunswick 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 Brunswick?

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

6.6
Sightseeing
3rd-best month of the year
3.8
Beach & pool
4th-best month of the year

September is a reasonable time to visit Brunswick for sightseeing.

What to pack for Brunswick in September

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

In September, Brunswick sees daytime highs around 69°F and nights near 54°F. Worth packing: rain gear. About 9 days see rain.

rain gear

Sea temperature near Brunswick in September

The nearest coast averages about 58°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 17 mi away) is warmest in August at about 62°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°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan41Bracing
Feb38Bracing
Mar38Bracing
Apr41Bracing
May47Bracing
Jun54Bracing
Jul60Cool
Aug62Cool
Sep58Bracing
Oct54Bracing
Nov49Bracing
Dec45Bracing

UV index in Brunswick in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Brunswick peaks around July 12 at about 7 (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 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateModerateLowJul 12UV 7Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5Moderate
May7High
Jun6High
Jul7Very high
Aug4Moderate
Sep5High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Brunswick?

Brunswick sits at 43.9°N, 70.0°W, 62 ft above sea level, in United States. The nearest listed city is Lewiston, 18 mi away.

Topography around Brunswick

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

Within 2 miles, the terrain around Brunswick has only modest variations in elevation — a maximum elevation change of 249 ft around an average of 92 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 456 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,526 ft.

The land around Brunswick is covered by trees (60%) within 2 miles, trees (68%) within 10 miles, and trees (62%) and water (33%) within 50 miles.

2 miles
249 ft
10 miles
456 ft
50 miles
2,526 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Lewiston 18 mi · Auburn 18 mi · Portland 23 mi · South Portland 24 mi · South Portland Gardens 26 mi · Westbrook 26 mi · Augusta 29 mi · West Scarborough 32 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 Brunswick (43.9145°, -69.9653°, 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).