Iselin weather in August

In August, Iselin sees average daytime highs of 82°F and overnight lows near 69°F, with 4.1 in of rain across 10.6 wet days and about 13.6 hours of daylight. It is the 2nd-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 84°F in the first days to 81°F by the end. The sky is clear or mostly clear about 30% of the time in August, and the air most often feels muggy.

Daylight stretches from about 14 h 12 min at the start of August to 13 hours by month's end. Set against the rest of the year, August is Iselin's 4th-clearest and 12th-windiest month. For the whole year in context, see Iselin's year-round climate.

Daytime high
82°
2nd warmest
Overnight low
69°
11th coldest
Rainfall
4.1 in
10.6 wet days
Daylight
13 h 36 min
5:13 AM – 6:50 PM
Cloud cover
57%
4th clearest
Wind
6 mph
12th windiest
Solar energy
5.17 kWh/m²
Travel score
6.0
out of 10

Iselin is unincorporated community in New Jersey, United States.

Density
2,262/km²
people per km²

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 84°F in the first days to 81°F by the end.

A typical August day in Iselin reaches about 82°F in the afternoon and slips back to 69°F overnight — a 13°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 89°F. Set against its neighbours, August runs about 2°F cooler than July and about 7°F warmer than September.

60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18471
28471
38471
48470
58470
68370
78370
88370
98370
108370
118370
128369
138369
148369
158269
168269
178269
188269
198269
208268
218268
228268
238268
248168
258168
268167
278167
288167
298167
308067
318067

How August really feels in Iselin

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.

Iselin weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan39° / 27°3.29.23.99.40.0
Feb42° / 28°3.08.53.410.40.3
Mar49° / 35°4.210.42.811.72.0
Apr61° / 46°3.610.60.3134.8
May70° / 55°3.411.1014.26.3
Jun79° / 65°4.011.1014.86.3
Jul84° / 71°4.111.3014.65.2
Aug82° / 69°4.110.6013.66.0
Sep76° / 62°3.79.2012.37.0
Oct65° / 51°3.78.5010.96.0
Nov53° / 40°3.07.80.39.73.3
Dec44° / 32°3.99.529.20.8

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 30% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 21% of August, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14951
24951
34951
44951
54951
64951
74852
84852
94852
104852
114852
124852
134951
144951
155050
165050
175149
185149
195347
205347
215446
225446
235545
245644
255644
265545
275545
285545
295545
305545
315446

Chance of precipitation in August

Any precipitation

Iselin gets around 4.1 in of rain over 10.6 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 34% and peaks near 38% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
138
238
338
438
538
638
738
838
938
1038
1138
1238
1338
1438
1537
1637
1736
1835
1934
2033
2133
2232
2331
2430
2529
2628
2728
2827
2927
3027
3127

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the muggy band about 32% of days. Sticky, muggy-or-worse air turns up on roughly 52% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
13122536241
23122535241
33132535241
44132534241
54132534241
64132534241
74132433241
85132433241
95142433241
105142433231
115142433231
125142433221
136142433221
146152433211
156152434211
166162434201
176162434191
186172434191
196172534181
206182533180
216182533170
226192532170
237202532160
247202631160
258212630160
268222629150
279222628150
289222627150
2910222626150
3010232626150
3111232625150

Wind in August

Winds average 6 mph in August, the calmest month.

Across August, 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.

0246810151015202531
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
316calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 12 min at the start of August to 13 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 72 minutes over August. Sunrise moves from 4:58 AM to 5:28 AM, and sunset from 7:09 PM to 6:27 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.24:587:09
214.24:597:08
314.15:007:07
414.15:017:06
514.05:027:04
614.05:037:03
714.05:047:02
813.95:057:01
913.95:067:00
1013.95:076:58
1113.85:086:57
1213.85:096:56
1313.75:106:54
1413.75:116:53
1513.75:126:52
1613.65:136:50
1713.65:146:49
1813.55:156:47
1913.55:166:46
2013.55:176:44
2113.45:186:43
2213.45:196:41
2313.35:206:40
2413.35:216:38
2513.35:226:37
2613.25:236:35
2713.25:246:34
2813.15:256:32
2913.15:266:30
3013.05:276:29
3113.05:286:27

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.17 kWh/m².

For context, solar energy here swings from a low near 1.77 kWh/m² to a high of 5.95 kWh/m² in June across the year — August's 5.17 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.5Bright
25.5Bright
35.4Bright
45.4Bright
55.4Bright
65.4Bright
75.3Bright
85.3Bright
95.3Bright
105.3Bright
115.2Bright
125.2Bright
135.2Bright
145.2Bright
155.1Bright
165.1Bright
175.1Bright
185.1Bright
195.1Bright
205.0Bright
215.0Bright
225.0Bright
235.0Bright
245.0Bright
255.0Bright
264.9Bright
274.9Bright
284.9Bright
294.8Bright
304.8Bright
314.8Bright
Planning a trip in August

Hazard calendar for Iselin

In seasonPeak

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

Iselin 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 Iselin?

Our two travel scores rate August 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
2nd-best month of the year

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

What to pack for Iselin in August

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

In August, Iselin sees daytime highs around 82°F and nights near 69°F. Pack light clothes. Worth having: rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

Sea temperature near Iselin in August

The nearest coast averages about 74°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 24 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 Iselin in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Iselin 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 21 at about 1 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 8Dec 21UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov3Moderate
Dec1Low

Air quality in Iselin 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 Iselin is worst in July — around 18 µg/m³ PM2.5 (moderate), about 1.8× the cleanest month (November, 10 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodJul 1318 µg/m³Nov 1410 µg/m³
PM2.5 (µg/m³)Level
Jan12Moderate
Feb15Moderate
Mar16Moderate
Apr16Moderate
May17Moderate
Jun17Moderate
Jul18Moderate
Aug16Moderate
Sep14Moderate
Oct11Good
Nov10Good
Dec12Good
Location & terrain

Where is Iselin?

Iselin sits at 40.6°N, 74.3°W, 62 ft above sea level, in United States. The nearest listed city is Colonia, 1.2 mi away.

Topography around Iselin

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

Within 2 miles, the terrain around Iselin has only modest variations in elevation — a maximum elevation change of 200 ft around an average of 102 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 630 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,847 ft.

The land around Iselin is covered by trees (49%) and artificial surfaces (39%) within 2 miles, trees (46%) and artificial surfaces (33%) within 10 miles, and trees (56%) and water (21%) within 50 miles.

2 miles
200 ft
10 miles
630 ft
50 miles
1,847 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
August weather nearby: Colonia 1.2 mi · Avenel 1.9 mi · Woodbridge 2.5 mi · Fords 3.1 mi · Rahway 3.1 mi · South Plainfield 5.0 mi · Carteret 5.0 mi · Linden 5.0 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 Iselin (40.5754°, -74.3224°, 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).