Rotterdam weather in September

In September, Rotterdam sees average daytime highs of 72°F and overnight lows near 53°F, with 4.2 in of rain across 9.6 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 76°F in the first days to 67°F by the end. The sky is clear or mostly clear about 34% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Rotterdam's 1st-clearest and 10th-windiest month. For the whole year in context, see Rotterdam's year-round climate.

Daytime high
72°
4th warmest
Overnight low
53°
9th coldest
Rainfall
4.2 in
9.6 wet days
Daylight
12 h 18 min
5:42 AM – 5:59 PM
Cloud cover
57%
1st clearest
Wind
5 mph
10th windiest
Solar energy
4.08 kWh/m²
Travel score
6.7
out of 10

Rotterdam is census-designated place in Schenectady County, New York, United States.

Density
1,151/km²
people per km²

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 76°F in the first days to 67°F by the end.

A typical September day in Rotterdam reaches about 72°F in the afternoon and slips back to 53°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 62°F and 82°F. Set against its neighbours, September runs about 7°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17658
27657
37657
47657
57557
67556
77556
87456
97455
107455
117355
127354
137354
147254
157253
167253
177152
187152
197152
207051
217051
226951
236950
246950
256849
266849
276749
286748
296648
306648

How September really feels in Rotterdam

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.

Rotterdam 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
Jan31° / 17°3.09.87.19.20.0
Feb34° / 18°2.896.610.30.0
Mar43° / 26°3.811.25.311.60.6
Apr56° / 38°4.1121.713.13.7
May67° / 48°4.112.50.114.45.8
Jun76° / 57°4.812.8015.16.3
Jul80° / 62°4.412014.86.2
Aug79° / 60°4.211.5013.76.6
Sep72° / 53°4.29.6012.36.7
Oct59° / 42°4.510.80.410.84.5
Nov47° / 32°3.39.82.19.61.5
Dec36° / 23°3.810.86.28.90.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 49%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15446
25446
35446
45347
55347
65347
75347
85248
95347
105347
115347
125248
135248
145248
155248
165149
175149
185149
195149
205050
215050
224852
234852
244852
254951
264951
274852
284852
294852
304951

Chance of precipitation in September

Any precipitation

Rotterdam gets around 4.2 in of rain over 9.6 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 32% and peaks near 35% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
130
230
330
430
530
630
730
830
930
1031
1131
1231
1331
1431
1531
1632
1732
1832
1932
2033
2133
2233
2334
2434
2534
2635
2735
2835
2935
3035

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 55% of days. Sticky, muggy-or-worse air turns up on roughly 8% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1342921151
2352921141
3362821141
4372821131
5392820131
6402720121
7412719121
8432719111
9442619101
10462518101
1147251891
1249241890
1351231880
1452231780
1554221770
1656211670
1758201660
1859201560
1960191560
2063181450
2164171450
2265171350
2367161340
2469151240
2570151140
2672141130
2773141030
287513930
297613830
307812820

Wind in September

Winds average 5 mph in September.

Across September, daily wind ranges from about 5 mph on the calmest days to 6 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours 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 84 minutes over September. Sunrise moves from 5:25 AM to 5:57 AM, and sunset from 6:26 PM to 5:33 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:256:26
213.05:266:24
312.95:276:23
412.95:286:21
512.85:296:19
612.85:306:17
712.75:326:15
812.75:336:14
912.65:346:12
1012.65:356:10
1112.55:366:08
1212.55:376:06
1312.45:386:04
1412.45:396:03
1512.35:416:01
1612.35:425:59
1712.25:435:57
1812.25:445:55
1912.15:455:53
2012.15:465:51
2112.05:475:49
2212.05:485:48
2311.95:495:46
2411.95:515:44
2511.85:525:42
2611.85:535:40
2711.75:545:38
2811.75:555:37
2911.65:565:35
3011.65:575:33

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.08 kWh/m².

For context, solar energy here swings from a low near 1.44 kWh/m² to a high of 5.93 kWh/m² in July across the year — September's 4.08 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.6Bright
44.6Bright
54.5Bright
64.5Bright
74.5Bright
84.4Bright
94.4Bright
104.3Bright
114.3Bright
124.2Bright
134.2Bright
144.2Bright
154.1Bright
164.1Bright
174.0Bright
184.0Moderate
194.0Moderate
203.9Moderate
213.9Moderate
223.8Moderate
233.8Moderate
243.7Moderate
253.7Moderate
263.6Moderate
273.6Moderate
283.5Moderate
293.5Moderate
303.4Moderate
Planning a trip in September

Is September a good time to visit Rotterdam?

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

6.7
Sightseeing
1st-best month of the year
4.6
Beach & pool
4th-best month of the year

September is a reasonable time to visit Rotterdam for sightseeing.

What to pack for Rotterdam in September

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

In September, Rotterdam sees daytime highs around 72°F and nights near 53°F. Worth packing: light clothes and rain gear. About 10 days see rain.

light clothesrain gear

UV index in Rotterdam 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 Rotterdam peaks around July 12 at about 8 (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 highHighModerateLowJul 12UV 8Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May7Very high
Jun7Very high
Jul8Very high
Aug5Moderate
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low
Location & terrain

Where is Rotterdam?

Rotterdam sits at 42.8°N, 74.0°W, 338 ft above sea level, in United States. The nearest listed city is Schenectady, 2.5 mi away.

Topography around Rotterdam

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

Within 2 miles, the terrain around Rotterdam has only modest variations in elevation — a maximum elevation change of 220 ft around an average of 328 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,440 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,058 ft.

The land around Rotterdam is covered by trees (47%) and artificial surfaces (35%) within 2 miles, trees (72%) within 10 miles, and trees (83%) within 50 miles.

2 miles
220 ft
10 miles
1,440 ft
50 miles
4,058 ft
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Schenectady 2.5 mi · Glenville 11 mi · Latham 11 mi · Clifton Park 12 mi · West Albany 12 mi · Cohoes 14 mi · Albany 14 mi · Troy 15 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 Rotterdam (42.787°, -73.971°, elevation 338 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. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).