Marlborough weather in September

In September, Marlborough sees average daytime highs of 73°F and overnight lows near 56°F, with 3.4 in of rain across 7.7 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 78°F in the first days to 69°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 Marlborough's 1st-clearest and 10th-windiest month. For the whole year in context, see Marlborough's year-round climate.

Daytime high
73°
4th warmest
Overnight low
56°
9th coldest
Rainfall
3.4 in
7.7 wet days
Daylight
12 h 18 min
5:32 AM – 5:49 PM
Cloud cover
55%
1st clearest
Wind
6 mph
10th windiest
Solar energy
4.11 kWh/m²
Travel score
7.1
out of 10

Marlborough is city in Middlesex County, Massachusetts, United States.

Density
696/km²
people per km²
Founded
1657

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 69°F by the end.

A typical September day in Marlborough reaches about 73°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 64°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)
17860
27860
37860
47759
57759
67759
77659
87658
97658
107558
117557
127557
137456
147456
157456
167356
177355
187355
197255
207254
217154
227154
237153
247053
257053
267052
276952
286951
296851
306851

How September really feels in Marlborough

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.

Marlborough 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
Jan36° / 21°3.39.45.99.30.0
Feb38° / 22°3.08.45.210.30.0
Mar46° / 29°4.210.64.711.61.2
Apr58° / 40°3.610.9113.14.0
May67° / 49°3.010.4014.46.1
Jun77° / 59°3.510.80156.5
Jul83° / 65°3.110.3014.85.8
Aug81° / 63°3.59.2013.76.6
Sep73° / 56°3.47.7012.37.1
Oct62° / 45°3.89.30.210.85.4
Nov50° / 35°3.48.90.99.62.4
Dec40° / 27°4.110.54.990.2

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 14% of September, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25248
35149
45149
55149
65149
75149
85149
95248
105248
115248
125347
135248
145248
155347
165347
175248
185248
195149
205248
215248
225149
235149
245149
255149
265149
275149
285149
295149
305149

Chance of precipitation in September

Any precipitation

Marlborough gets around 3.4 in of rain over 7.7 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 26% and peaks near 28% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
123
224
324
424
525
625
726
826
926
1027
1127
1227
1326
1426
1526
1626
1725
1825
1925
2025
2125
2225
2325
2426
2526
2626
2727
2827
2928
3028

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 52% of days. Sticky, muggy-or-worse air turns up on roughly 11% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1342721144
2352720143
3362720143
4372620133
5392619133
6402619133
7412519132
8422419132
9432419122
10442319122
11452319121
12472218121
13482118121
14492118111
15512017111
16512017111
17541916101
18541916101
19561915100
2058181590
2159181490
2261181380
2361181380
2463181270
2564171270
2666171160
2766171160
2868171050
2969161050
307116940

Wind in September

Winds average 6 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
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
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 5:16 AM to 5:48 AM, and sunset from 6:16 PM to 5:23 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:166:16
213.05:176:14
312.95:186:13
412.95:196:11
512.85:206:09
612.85:216:07
712.75:226:05
812.75:236:04
912.65:246:02
1012.65:266:00
1112.55:275:58
1212.55:285:56
1312.45:295:54
1412.45:305:53
1512.35:315:51
1612.35:325:49
1712.25:335:47
1812.25:345:45
1912.15:355:43
2012.15:365:42
2112.05:385:40
2212.05:395:38
2311.95:405:36
2411.95:415:34
2511.85:425:32
2611.85:435:31
2711.75:445:29
2811.75:455:27
2911.65:475:25
3011.65:485:23

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.11 kWh/m².

For context, solar energy here swings from a low near 1.61 kWh/m² to a high of 5.86 kWh/m² in June across the year — September's 4.11 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
84.4Bright
94.4Bright
104.3Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.2Bright
164.1Bright
174.1Bright
184.0Bright
194.0Bright
204.0Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.8Moderate
253.7Moderate
263.7Moderate
273.6Moderate
283.6Moderate
293.6Moderate
303.5Moderate
Planning a trip in September

Hazard calendar for Marlborough

In seasonPeak

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

Marlborough 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 Marlborough?

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

7.1
Sightseeing
1st-best month of the year
5.4
Beach & pool
4th-best month of the year

September is one of the better times to visit Marlborough for general sightseeing.

What to pack for Marlborough in September

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

In September, Marlborough sees daytime highs around 73°F and nights near 56°F. Worth packing: light clothes. About 8 days see rain.

light clothes

Sea temperature near Marlborough in September

The nearest coast averages about 63°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 35 mi away) is warmest in August at about 66°F and coldest in February 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
Jan41Bracing
Feb38Bracing
Mar38Bracing
Apr42Bracing
May50Bracing
Jun58Bracing
Jul65Cool
Aug66Cool
Sep63Cool
Oct56Bracing
Nov50Bracing
Dec46Bracing

UV index in Marlborough 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 Marlborough 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 10UV 7Dec 23UV 1
UV index (midday)Level
Jan1Low
Feb3Moderate
Mar4Moderate
Apr5High
May7Very high
Jun7Very high
Jul7Very high
Aug5Moderate
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Marlborough 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 Marlborough is worst in July — around 16 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1516 µg/m³Nov 189 µg/m³
PM2.5 (µg/m³)Level
Jan10Good
Feb13Moderate
Mar14Moderate
Apr14Moderate
May15Moderate
Jun15Moderate
Jul16Moderate
Aug14Moderate
Sep12Good
Oct10Good
Nov8Good
Dec10Good
Location & terrain

Where is Marlborough?

Marlborough sits at 42.3°N, 71.6°W, 390 ft above sea level, in United States. The nearest listed city is Framingham Center, 6.8 mi away.

Topography around Marlborough

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

Within 2 miles, the terrain around Marlborough has only modest variations in elevation — a maximum elevation change of 381 ft around an average of 387 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 689 ft; within 50 miles, large variations in elevation — a maximum elevation change of 3,176 ft.

The land around Marlborough is covered by trees (68%) within 2 miles, trees (81%) within 10 miles, and trees (81%) within 50 miles.

2 miles
381 ft
10 miles
689 ft
50 miles
3,176 ft
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Framingham Center 6.8 mi · Ashland 7.5 mi · Sudbury 7.5 mi · Framingham 8.1 mi · Shrewsbury 8.7 mi · Natick 11 mi · Acton 11 mi · Grafton 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 Marlborough (42.3459°, -71.5523°, elevation 390 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).