Iselin in Fall
In fall (September, October and November), Iselin sees average daytime highs around 65°F and overnight lows near 51°F, with 10.4 in of precipitation over about 26 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 80°F in early September to 49°F by late November. The sky is clear or mostly clear about 37% of the time across fall, and the air most often feels dry.
Fall is Iselin's 2nd-best season to visit on our travel score. For the whole year in context, see Iselin's year-round climate.
- Avg daytime high
- 65°F
- 2nd-warmest season
- Avg overnight low
- 51°F
- Precipitation
- 10.4 in
- 26 wet days
- Avg wind
- 7 mph
- Travel score
- 5.4
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Iselin in Fall
Over the season highs ease from about 80°F in early September to 49°F by late November.
A typical fall day in Iselin reaches about 65°F and drops to 51°F overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Iselin
Once humidity and wind are folded in, fall brings about 0 days that feel above 90°F and 6 that feel at or below 32°F.
The story in fall is cold — wind chill drags the overnight "feels like" below the raw low.
Iselin weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 39° / 27° | 3.2 | 9.2 | 3.9 | 9.4 | 0.0 |
| Feb | 42° / 28° | 3.0 | 8.5 | 3.4 | 10.4 | 0.3 |
| Mar | 49° / 35° | 4.2 | 10.4 | 2.8 | 11.7 | 2.0 |
| Apr | 61° / 46° | 3.6 | 10.6 | 0.3 | 13 | 4.8 |
| May | 70° / 55° | 3.4 | 11.1 | 0 | 14.2 | 6.3 |
| Jun | 79° / 65° | 4.0 | 11.1 | 0 | 14.8 | 6.3 |
| Jul | 84° / 71° | 4.1 | 11.3 | 0 | 14.6 | 5.2 |
| Aug | 82° / 69° | 4.1 | 10.6 | 0 | 13.6 | 6.0 |
| Sep | 76° / 62° | 3.7 | 9.2 | 0 | 12.3 | 7.0 |
| Oct | 65° / 51° | 3.7 | 8.5 | 0 | 10.9 | 6.0 |
| Nov | 53° / 40° | 3.0 | 7.8 | 0.3 | 9.7 | 3.3 |
| Dec | 44° / 32° | 3.9 | 9.5 | 2 | 9.2 | 0.8 |
Cloud cover in Fall
The sky is clear or mostly clear about 37% of the time across fall.
Chance of precipitation in Fall
Iselin gets around 10.4 in of rain and snow over 26 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 7 mph across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 54 min in early September to 9 h 18 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 3.2 kWh/m².
Hazard calendar for Iselin
In fall, Iselin overlaps 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.
Is fall a good time to visit Iselin?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit Iselin for sightseeing.
What to pack for Iselin in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Iselin sees daytime highs around 65°F and nights near 51°F. Pack a warm layer. Worth having: light clothes and rain gear. About 26 days see rain.
Sea temperature near Iselin in Fall
The nearest coast averages about 63°F across fall — 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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 43 | 40 | 41 | 46 | 55 | 65 | 72 | 74 | 71 | 63 | 55 | 48 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Refreshing | Refreshing | Cool | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 43 | Bracing |
| Feb | 40 | Bracing |
| Mar | 41 | Bracing |
| Apr | 46 | Bracing |
| May | 55 | Bracing |
| Jun | 65 | Cool |
| Jul | 72 | Refreshing |
| Aug | 74 | Refreshing |
| Sep | 71 | Refreshing |
| Oct | 63 | Cool |
| Nov | 55 | Bracing |
| Dec | 48 | Bracing |
UV index in Iselin in Fall
Clear-sky midday UV across fall averages around 4 — 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.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 5 | 6 | 7 | 8 | 8 | 6 | 6 | 3 | 3 | 1 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | Very high | High | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 5 | Moderate |
| Apr | 6 | High |
| May | 7 | Very high |
| Jun | 8 | Very high |
| Jul | 8 | Very high |
| Aug | 6 | High |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 3 | Moderate |
| Dec | 1 | Low |
Air quality in Iselin in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall 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).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 12 | 15 | 16 | 16 | 17 | 17 | 18 | 16 | 14 | 11 | 10 | 12 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 12 | Moderate |
| Feb | 15 | Moderate |
| Mar | 16 | Moderate |
| Apr | 16 | Moderate |
| May | 17 | Moderate |
| Jun | 17 | Moderate |
| Jul | 18 | Moderate |
| Aug | 16 | Moderate |
| Sep | 14 | Moderate |
| Oct | 11 | Good |
| Nov | 10 | Good |
| Dec | 12 | Good |
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.
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
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.