Watertown weather in July

In July, Watertown sees average daytime highs of 82°F and overnight lows near 65°F, with 3.0 in of rain across 10.5 wet days and about 14.8 hours of daylight. It is the 1st-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 82°F through the month. The sky is clear or mostly clear about 26% of the time in July, and the air most often feels humid.

Daylight stretches from about 15 h 06 min at the start of July to 14 h 24 min by month's end. Set against the rest of the year, July is Watertown's 8th-clearest and 11th-windiest month. For the whole year in context, see Watertown's year-round climate.

Daytime high
82°
1st warmest
Overnight low
65°
12th coldest
Rainfall
3.0 in
10.5 wet days
Daylight
14 h 48 min
4:26 AM – 7:15 PM
Cloud cover
60%
8th clearest
Wind
6 mph
11th windiest
Solar energy
5.88 kWh/m²
Travel score
6.0
out of 10

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

Density
2,994/km²
people per km²
Founded
1630

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

Temperature in July

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 82°F through the month.

A typical July day in Watertown reaches about 82°F in the afternoon and slips back to 65°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 73°F and 91°F. Set against its neighbours, July runs about 6°F warmer than June and about 2°F warmer than August.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18164
28264
38264
48264
58264
68265
78265
88265
98265
108265
118265
128265
138365
148365
158365
168365
178365
188366
198366
208366
218366
228366
238366
248366
258366
268366
278266
288266
298266
308266
318266

How July really feels in Watertown

Once humidity and wind are folded in, July 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

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

Watertown weather by month

How July compares with the rest of the year at a glance. July is the 1st-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan36° / 22°3.49.75.79.30.0
Feb38° / 23°3.08.65.110.30.0
Mar46° / 30°4.310.94.711.61.1
Apr57° / 40°3.610.9113.13.9
May67° / 50°3.010.3014.46.0
Jun76° / 59°3.410.70156.6
Jul82° / 65°3.010.5014.86.0
Aug80° / 64°3.59.6013.76.6
Sep73° / 56°3.48.1012.37.1
Oct62° / 46°3.99.40.210.85.4
Nov51° / 36°3.49.10.89.62.5
Dec41° / 28°4.210.54.690.2

Cloud cover in July

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in July.

Beyond those clear spells, partly cloudy skies cover about 23% of July, with mostly cloudy or overcast conditions the remaining 51%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14852
24852
34951
44852
54852
65050
75050
85149
95149
105149
115050
125050
135050
145050
155050
165050
175050
184951
194951
204951
214852
224852
234852
244852
254852
264951
275050
285050
295050
305149
315248

Chance of precipitation in July

Any precipitation

Watertown gets around 3.0 in of rain over 10.5 wet days in July. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 34% and peaks near 36% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
133
233
332
432
532
632
732
832
932
1033
1133
1233
1334
1434
1534
1634
1735
1835
1935
2035
2135
2236
2336
2436
2536
2636
2736
2836
2936
3036
3136

Humidity in July

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, July lands in the humid band about 29% of days. Sticky, muggy-or-worse air turns up on roughly 34% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1222328235
2212328236
3202328236
4202428226
5192428227
6192428227
7182428227
8172429227
9172528238
10162528238
11162429238
12152429248
13142429248
14142429259
15142429259
16132329269
17132329269
18122229279
191222292710
201222292810
211121302810
221121302810
231120302910
241120302910
251120302910
261120302910
271119302910
281219302910
291219302910
301319292910
311319292910

Wind in July

Winds average 6 mph in July.

Across July, 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.

0246810151015202531
Wind speed (mph)Feels
17calm
27calm
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
316calm

Sunrise & sunset in July

DaylightNight

Daylight runs from about 15 h 06 min at the start of July to 14 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 42 minutes over July. Sunrise moves from 4:16 AM to 4:40 AM, and sunset from 7:20 PM to 7:02 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
115.14:167:20
215.14:177:20
315.04:177:20
415.04:187:20
515.04:187:19
615.04:197:19
715.04:197:19
815.04:207:19
915.04:217:18
1014.94:217:18
1114.94:227:17
1214.94:237:17
1314.94:247:16
1414.94:247:16
1514.84:257:15
1614.84:267:15
1714.84:277:14
1814.84:287:13
1914.74:287:13
2014.74:297:12
2114.74:307:11
2214.74:317:10
2314.64:327:10
2414.64:337:09
2514.64:347:08
2614.54:357:07
2714.54:367:06
2814.54:377:05
2914.44:387:04
3014.44:397:03
3114.44:407:02

Solar energy in July

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in July, about 5.88 kWh/m² — the sunniest month for solar.

For context, solar energy here swings from a low near 1.62 kWh/m² to a high of 5.88 kWh/m² in July across the year — July's 5.88 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
16.1Intense
26.1Intense
36.1Intense
46.1Intense
56.1Intense
66.1Intense
76.1Intense
86.1Intense
96.0Intense
106.0Intense
116.0Intense
126.0Bright
136.0Bright
145.9Bright
155.9Bright
165.9Bright
175.8Bright
185.8Bright
195.8Bright
205.8Bright
215.7Bright
225.7Bright
235.7Bright
245.7Bright
255.6Bright
265.6Bright
275.6Bright
285.6Bright
295.5Bright
305.5Bright
315.5Bright
Planning a trip in July

Hazard calendar for Watertown

In seasonPeak

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

Watertown 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 July a good time to visit Watertown?

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

6.0
Sightseeing
4th-best month of the year
6.7
Beach & pool
1st-best month of the year

July is a reasonable time to visit Watertown for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Watertown in July

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

In July, Watertown sees daytime highs around 82°F and nights near 65°F. Pack light clothes. Worth having: rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

Sea temperature near Watertown in July

The nearest coast averages about 65°F in July — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 16 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 Watertown in July

LowModerateHighVery highExtreme

Clear-sky midday UV in July peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Watertown 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 Watertown in July

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Watertown 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 Watertown?

Watertown sits at 42.4°N, 71.2°W, 62 ft above sea level, in United States. The nearest listed city is Belmont, 1.9 mi away.

Topography around Watertown

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

Within 2 miles, the terrain around Watertown has only modest variations in elevation — a maximum elevation change of 335 ft around an average of 85 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 2,454 ft.

The land around Watertown is covered by trees (48%) and artificial surfaces (43%) within 2 miles, trees (60%) and artificial surfaces (27%) within 10 miles, and trees (66%) and water (25%) within 50 miles.

2 miles
335 ft
10 miles
486 ft
50 miles
2,454 ft
treesgrasslandartificial surfaceswaterwetland
July weather nearby: Belmont 1.9 mi · Brighton 1.9 mi · Newton 2.5 mi · Waltham 2.5 mi · Chestnut Hill 3.1 mi · Allston 3.1 mi · Arlington 3.1 mi · Cambridge 3.7 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 Watertown (42.3709°, -71.1828°, 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. 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).