Deux-Montagnes weather in September

In September, Deux-Montagnes sees average daytime highs of 20°C and overnight lows near 12°C, with 93 mm of rain across 10.3 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 23°C in the first days to 17°C by the end. The sky is clear or mostly clear about 32% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Deux-Montagnes's 1st-clearest and 9th-windiest month. For the whole year in context, see Deux-Montagnes's year-round climate.

Daytime high
20°
4th warmest
Overnight low
12°
9th coldest
Rainfall
93 mm
10.3 wet days
Daylight
12 h 18 min
5:40 AM – 5:59 PM
Cloud cover
57%
1st clearest
Wind
11 km/h
9th windiest
Solar energy
3.87 kWh/m²
Travel score
6.3
out of 10

Deux-Montagnes is city in Quebec, Canada.

Density
2,384/km²
people per km²
Founded
1921

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 23°C in the first days to 17°C by the end.

A typical September day in Deux-Montagnes reaches about 20°C in the afternoon and slips back to 12°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 25°C. Set against its neighbours, September runs about 4°C cooler than August and about 7°C warmer than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
12314
22314
32314
42214
52214
62213
72213
82213
92213
102113
112112
122112
132112
142112
152012
162011
172011
182011
192011
201911
211911
221910
231910
241810
251810
261810
27189
28179
29179
30179

How September really feels in Deux-Montagnes

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
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.

Deux-Montagnes weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-5° / -14°7510.59.48.90.0
Feb-4° / -13°618.98.210.10.0
Mar / -6°7410.26.711.60.0
Apr10° / 10311.72.813.22.1
May18° / 9511.50.114.75.3
Jun23° / 14°10311.9015.46.4
Jul26° / 17°9112.5015.16.4
Aug25° / 16°9311.3013.96.8
Sep20° / 12°9310.3012.36.3
Oct13° / 10811.60.610.73.3
Nov / -1°8711.63.79.30.5
Dec-2° / -8°8611.59.28.60.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 32% 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 52%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15248
25248
35149
45149
55050
65149
75149
85050
95050
105050
115050
124951
134951
144951
154951
164951
174951
184951
194951
204852
214852
224753
234753
244654
254555
264456
274357
284258
294258
304159

Chance of precipitation in September

Any precipitation

Deux-Montagnes gets around 93 mm of rain over 10.3 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 34% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
130
231
331
432
532
633
733
834
934
1034
1134
1235
1335
1435
1535
1635
1735
1835
1935
2035
2135
2235
2335
2435
2536
2636
2736
2836
2936
3037

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 61% of days. Sticky, muggy-or-worse air turns up on roughly 6% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1392819131
2412818121
3422718121
4442717111
5452717101
647271691
748271691
850261680
952261570
1053251570
1154251560
1256241460
1358231450
1458231450
1561221340
1662211340
1763211240
1864201240
1966201130
2067191130
2169181030
2270171030
237217920
247416820
257515820
267714720
277813720
288112610
298211610
308410510

Wind in September

Winds average 11 km/h in September.

Across September, daily wind ranges from about 11 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1912calm
2012calm
2112calm
2212calm
2312calm
2412calm
2512calm
2612calm
2712calm
2812calm
2912light breeze
3012light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 96 minutes over September. Sunrise moves from 5:22 AM to 5:58 AM, and sunset from 6:29 PM to 5:31 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:226:29
213.15:236:27
313.05:246:25
413.05:256:23
512.95:276:21
612.95:286:19
712.85:296:17
812.85:306:15
912.75:326:13
1012.65:336:11
1112.65:346:09
1212.55:356:07
1312.55:376:05
1412.45:386:03
1512.45:396:01
1612.35:405:59
1712.35:425:57
1812.25:435:55
1912.25:445:53
2012.15:465:51
2112.05:475:49
2212.05:485:47
2311.95:495:45
2411.95:515:43
2511.85:525:41
2611.85:535:39
2711.75:555:37
2811.75:565:35
2911.65:575:33
3011.55:585:31

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.87 kWh/m².

For context, solar energy here swings from a low near 1.23 kWh/m² to a high of 5.92 kWh/m² in June across the year — September's 3.87 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.5Bright
24.5Bright
34.5Bright
44.4Bright
54.4Bright
64.3Bright
74.3Bright
84.2Bright
94.2Bright
104.1Bright
114.1Bright
124.0Bright
134.0Bright
144.0Moderate
153.9Moderate
163.9Moderate
173.8Moderate
183.8Moderate
193.7Moderate
203.7Moderate
213.6Moderate
223.6Moderate
233.5Moderate
243.5Moderate
253.4Moderate
263.3Moderate
273.3Moderate
283.2Moderate
293.2Moderate
303.1Moderate
Planning a trip in September

Is September a good time to visit Deux-Montagnes?

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

6.3
Sightseeing
4th-best month of the year
3.4
Beach & pool
4th-best month of the year

September is a reasonable time to visit Deux-Montagnes for sightseeing.

What to pack for Deux-Montagnes in September

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

In September, Deux-Montagnes sees daytime highs around 20°C and nights near 12°C. Worth packing: rain gear. About 10 days see rain.

rain gear

UV index in Deux-Montagnes in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Deux-Montagnes peaks around July 13 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near January 10 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJul 13UV 8Jan 10UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr4Moderate
May6High
Jun6High
Jul8Very high
Aug4Moderate
Sep5High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Deux-Montagnes?

Deux-Montagnes sits at 45.5°N, 73.9°W, 29 m above sea level, in Canada. The nearest listed city is Saint-Eustache, 3.0 km away.

Topography around Deux-Montagnes

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Deux-Montagnes.

Within 3 km, the terrain around Deux-Montagnes has only modest variations in elevation — a maximum elevation change of 44 m around an average of 29 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 258 m; within 80 km, large variations in elevation — a maximum elevation change of 867 m.

The land around Deux-Montagnes is covered by trees (35%), artificial surfaces (27%) and water (26%) within 3 km, trees (34%) and artificial surfaces (23%) within 16 km, and trees (48%) and cropland (35%) within 80 km.

3 km
44 m
16 km
258 m
80 km
867 m
treesgrasslandcroplandartificial surfacesbare terrainwaterwetland
September weather nearby: Saint-Eustache 3.0 km · L'Île-Bizard–Sainte-Geneviève 5.0 km · Pierrefonds-Roxboro 6.0 km · Dollard-Des Ormeaux 8.0 km · Pierrefonds 8.0 km · Kirkland 10 km · Boisbriand 11 km · Beaconsfield 12 km

Canada travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 83% of US
price level, 2025
GDP per capita
$55,698
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
97%
of population, 2024
Homicide rate
2
per 100k, 2023
Road deaths
5.3
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 53%none 35%Muslim 5%Hindu 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 Deux-Montagnes (45.5346°, -73.9017°, elevation 29 m), 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).