Somerville weather in August

In August, Somerville sees average daytime highs of 77°F and overnight lows near 64°F, with 3.3 in of rain across 9 wet days and about 13.7 hours of daylight. It is the 2nd-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 78°F in the first days to 75°F by the end. The sky is clear or mostly clear about 35% of the time in August, and the air most often feels humid.

Daylight stretches from about 14 h 18 min at the start of August to 13 h 06 min by month's end. Set against the rest of the year, August is Somerville's 3rd-clearest and 12th-windiest month. For the whole year in context, see Somerville's year-round climate.

Daytime high
77°
2nd warmest
Overnight low
64°
11th coldest
Rainfall
3.3 in
9 wet days
Daylight
13 h 42 min
4:56 AM – 6:41 PM
Cloud cover
55%
3rd clearest
Wind
7 mph
12th windiest
Solar energy
5.3 kWh/m²
Travel score
7.1
out of 10

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

Density
7,348/km²
people per km²
Founded
1630

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 78°F in the first days to 75°F by the end.

A typical August day in Somerville reaches about 77°F in the afternoon and slips back to 64°F overnight — a 12°F spread between the day's warmth and the night's chill. On most days the high lands between 70°F and 84°F. Set against its neighbours, August runs on par with July and about 6°F warmer than September.

50°60°70°80°151015202531
Avg high (°F)Avg low (°F)
17866
27866
37866
47865
57865
67865
77865
87865
97765
107765
117765
127765
137765
147765
157765
167764
177764
187664
197664
207664
217664
227664
237663
247663
257663
267663
277563
287562
297562
307562
317562

How August really feels in Somerville

Once humidity and wind are folded in, August 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

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

Somerville weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan35° / 23°3.6105.89.30.0
Feb37° / 24°3.395.310.30.0
Mar43° / 31°4.511.34.511.60.6
Apr53° / 40°4.110.71.113.13.0
May63° / 49°3.310.7014.45.3
Jun72° / 59°3.510.30156.5
Jul78° / 65°2.99.9014.86.8
Aug77° / 64°3.39013.77.1
Sep70° / 58°3.48.2012.36.9
Oct60° / 47°4.310.10.210.84.9
Nov50° / 38°3.89.60.89.62.2
Dec40° / 29°4.510.54.590.2

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 35% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 20% of August, with mostly cloudy or overcast conditions the remaining 45%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15446
25545
35545
45545
55545
65545
75545
85347
95347
105347
115347
125347
135248
145248
155248
165347
175347
185446
195446
205545
215644
225644
235842
245842
255842
265842
275842
285941
295941
305842
315842

Chance of precipitation in August

Any precipitation

Somerville gets around 3.3 in of rain over 9 wet days in August. 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 33% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)
133
233
333
432
532
632
732
832
932
1032
1132
1232
1331
1431
1530
1630
1729
1829
1928
2028
2127
2227
2326
2426
2526
2626
2726
2825
2926
3026
3126

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the humid band about 30% of days. Sticky, muggy-or-worse air turns up on roughly 29% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
192231326
2102231326
3102231326
4102231316
5112231316
6112231306
7112231306
8112231296
9112232296
10122232286
11122332286
12122332275
13132332275
14132432265
15132433265
16132433254
17132533254
18142533254
19142632243
20152632243
21162731233
22162830233
23172830222
24182929212
25193028212
26203027202
27213127192
28223126192
29233126182
30243125182
31253125182

Wind in August

Winds average 7 mph in August, the calmest month.

Across August, daily wind ranges from about 7 mph on the calmest days to 8 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
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
287light breeze
297light breeze
308light breeze
318light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 18 min at the start of August to 13 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 72 minutes over August. Sunrise moves from 4:40 AM to 5:13 AM, and sunset from 7:00 PM to 6:16 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.34:407:00
214.34:426:59
314.34:436:58
414.24:446:57
514.24:456:56
614.14:466:54
714.14:476:53
814.14:486:52
914.04:496:51
1014.04:506:49
1113.94:516:48
1213.94:526:46
1313.94:536:45
1413.84:546:44
1513.84:556:42
1613.74:566:41
1713.74:586:39
1813.64:596:38
1913.65:006:36
2013.65:016:34
2113.55:026:33
2213.55:036:31
2313.45:046:30
2413.45:056:28
2513.35:066:26
2613.35:076:25
2713.25:086:23
2813.25:106:21
2913.15:116:20
3013.15:126:18
3113.15:136:16

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.3 kWh/m².

For context, solar energy here swings from a low near 1.57 kWh/m² to a high of 5.97 kWh/m² in July across the year — August's 5.3 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.6Bright
25.6Bright
35.5Bright
45.5Bright
55.5Bright
65.5Bright
75.5Bright
85.4Bright
95.4Bright
105.4Bright
115.3Bright
125.3Bright
135.3Bright
145.3Bright
155.3Bright
165.2Bright
175.2Bright
185.2Bright
195.2Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.1Bright
255.1Bright
265.1Bright
275.0Bright
285.0Bright
295.0Bright
304.9Bright
314.9Bright
Planning a trip in August

Hazard calendar for Somerville

In seasonPeak

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

Somerville 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 August a good time to visit Somerville?

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

7.1
Sightseeing
1st-best month of the year
6.3
Beach & pool
2nd-best month of the year

August is one of the better times to visit Somerville for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Somerville in August

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

In August, Somerville sees daytime highs around 77°F and nights near 64°F. Worth packing: light clothes, rain gear and sun protection. About 9 days see rain.

light clothesrain gearsun protection

Sea temperature near Somerville in August

The nearest coast averages about 66°F in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 11 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 Somerville in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Somerville 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 January 1 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 highHighHighModerateLowJul 10UV 7Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb3Moderate
Mar4Moderate
Apr5High
May7Very high
Jun7Very high
Jul7Very high
Aug5Moderate
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Somerville in August

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Somerville is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.0× the cleanest month (November, 8 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1715 µg/m³Nov 188 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb13Moderate
Mar13Moderate
Apr13Moderate
May14Moderate
Jun13Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct9Good
Nov8Good
Dec9Good
Location & terrain

Where is Somerville?

Somerville sits at 42.4°N, 71.1°W, 92 ft above sea level, in United States. The nearest listed city is Cambridge, 0.6 mi away.

Topography around Somerville

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

Within 2 miles, the terrain around Somerville has only modest variations in elevation — a maximum elevation change of 167 ft around an average of 33 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 486 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,060 ft.

The land around Somerville is covered by artificial surfaces (72%) within 2 miles, trees (45%) and artificial surfaces (30%) within 10 miles, and trees (63%) and water (28%) within 50 miles.

2 miles
167 ft
10 miles
486 ft
50 miles
2,060 ft
treesgrasslandartificial surfaceswaterwetland
August weather nearby: Cambridge 0.6 mi · Charlestown 1.9 mi · Medford 1.9 mi · Allston 2.5 mi · Back Bay 2.5 mi · Everett 2.5 mi · Boston 3.1 mi · Fenway/Kenmore 3.1 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 Somerville (42.3876°, -71.0995°, elevation 92 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).