Millburn weather in September

In September, Millburn sees average daytime highs of 75°F and overnight lows near 60°F, with 4.0 in of rain across 9.4 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 79°F in the first days to 71°F by the end. The sky is clear or mostly clear about 37% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 54 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Millburn's 2nd-clearest and 9th-windiest month. For the whole year in context, see Millburn's year-round climate.

Daytime high
75°
4th warmest
Overnight low
60°
9th coldest
Rainfall
4.0 in
9.4 wet days
Daylight
12 h 18 min
5:44 AM – 6:00 PM
Cloud cover
56%
2nd clearest
Wind
6 mph
9th windiest
Solar energy
4.15 kWh/m²
Travel score
6.9
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 79°F in the first days to 71°F by the end.

A typical September day in Millburn reaches about 75°F in the afternoon and slips back to 60°F overnight — a 15°F spread between the day's warmth and the night's chill. On most days the high lands between 67°F and 83°F. Set against its neighbours, September runs about 7°F cooler than August and about 11°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18065
27965
37965
47964
57964
67864
77864
87863
97763
107762
117762
127662
137661
147661
157561
167560
177560
187460
197459
207459
217358
227358
237358
247257
257257
267157
277156
287156
297055
307055

How September really feels in Millburn

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.

Millburn weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan38° / 25°3.49.24.69.40.0
Feb40° / 26°3.18.43.910.40.1
Mar48° / 34°4.210.23.511.71.8
Apr60° / 44°3.710.80.413.14.6
May70° / 54°3.611.7014.26.2
Jun79° / 64°4.111.2014.96.4
Jul84° / 69°4.211014.65.4
Aug82° / 68°4.010.7013.66.1
Sep75° / 60°4.09.4012.36.9
Oct64° / 49°3.98.70.110.95.8
Nov52° / 39°3.18.20.59.73.0
Dec43° / 31°4.09.739.10.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25248
35248
45248
55149
65149
75248
85248
95248
105248
115347
125347
135248
145347
155248
165347
175248
185248
195149
205149
215149
225149
235149
245149
255149
265248
275248
285248
295248
305347

Chance of precipitation in September

Any precipitation

Millburn gets around 4.0 in of rain over 9.4 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 30% and peaks near 31% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
128
228
329
429
529
629
730
830
930
1030
1130
1230
1330
1430
1530
1630
1730
1830
1930
2031
2131
2231
2331
2431
2531
2631
2731
2831
2931
3031

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 36% of days. Sticky, muggy-or-worse air turns up on roughly 20% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
11824252310
21825242210
31925242210
42025242110
5222523219
6232623209
7242622199
8252622198
9262622188
10282622187
11292621177
12312521176
13322521166
14342521155
15352421154
16372421144
17382321143
18402321133
19412321132
20432320122
21442220122
22462219112
23472219111
24492118111
25512117101
26512117101
2754201691
2854201691
2957191581
3057191581

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
206calm
216calm
226calm
236calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 54 min 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 78 minutes over September. Sunrise moves from 5:28 AM to 5:58 AM, and sunset from 6:25 PM to 5:35 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.95:286:25
212.95:296:24
312.95:306:22
412.85:316:20
512.85:326:19
612.75:336:17
712.75:346:15
812.65:356:13
912.65:366:12
1012.55:376:10
1112.55:396:08
1212.55:406:07
1312.45:416:05
1412.45:426:03
1512.35:436:01
1612.35:446:00
1712.25:455:58
1812.25:465:56
1912.15:475:54
2012.15:485:52
2112.05:495:51
2212.05:505:49
2311.95:515:47
2411.95:525:45
2511.85:535:44
2611.85:545:42
2711.85:555:40
2811.75:565:39
2911.75:575:37
3011.65:585:35

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.15 kWh/m².

For context, solar energy here swings from a low near 1.75 kWh/m² to a high of 5.92 kWh/m² in June across the year — September's 4.15 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.7Bright
44.6Bright
54.6Bright
64.5Bright
74.5Bright
84.5Bright
94.4Bright
104.4Bright
114.3Bright
124.3Bright
134.3Bright
144.2Bright
154.2Bright
164.2Bright
174.1Bright
184.1Bright
194.0Bright
204.0Bright
214.0Moderate
223.9Moderate
233.9Moderate
243.8Moderate
253.8Moderate
263.7Moderate
273.7Moderate
283.7Moderate
293.6Moderate
303.6Moderate
Planning a trip in September

Hazard calendar for Millburn

In seasonPeak

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

Millburn 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 Millburn?

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

6.9
Sightseeing
1st-best month of the year
5.7
Beach & pool
4th-best month of the year

September is a reasonable time to visit Millburn for sightseeing.

What to pack for Millburn in September

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

In September, Millburn sees daytime highs around 75°F and nights near 60°F. Worth packing: light clothes and rain gear. About 9 days see rain.

light clothesrain gear

Sea temperature near Millburn in September

The nearest coast averages about 71°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 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 Millburn 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 Millburn 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 22 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 11UV 8Dec 22UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Millburn 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 Millburn 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 Millburn?

Millburn sits at 40.7°N, 74.3°W, 144 ft above sea level, in United States. The nearest listed city is Maplewood, 1.9 mi away.

Topography around Millburn

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

Within 2 miles, the terrain around Millburn has only modest variations in elevation — a maximum elevation change of 545 ft around an average of 253 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 764 ft; within 50 miles, large variations in elevation — a maximum elevation change of 2,008 ft.

The land around Millburn is covered by trees (74%) and artificial surfaces (22%) within 2 miles, trees (58%) and artificial surfaces (30%) within 10 miles, and trees (60%) within 50 miles.

2 miles
545 ft
10 miles
764 ft
50 miles
2,008 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Maplewood 1.9 mi · South Orange 2.5 mi · Union 3.1 mi · Summit 3.1 mi · Irvington 3.7 mi · Hillside 4.3 mi · Cranford 4.3 mi · Orange 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 Millburn (40.7248°, -74.304°, elevation 144 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).