Saint-Jean-sur-Richelieu weather in September

In September, Saint-Jean-sur-Richelieu sees average daytime highs of 21°C and overnight lows near 11°C, with 98 mm of rain across 10.7 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 23°C in the first days to 18°C by the end. The sky is clear or mostly clear about 30% 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 36 min by month's end. Set against the rest of the year, September is Saint-Jean-sur-Richelieu's 2nd-clearest and 9th-windiest month. For the whole year in context, see Saint-Jean-sur-Richelieu's year-round climate.

Daytime high
21°
4th warmest
Overnight low
11°
9th coldest
Rainfall
98 mm
10.7 wet days
Daylight
12 h 18 min
5:38 AM – 5:57 PM
Cloud cover
58%
2nd clearest
Wind
11 km/h
9th windiest
Solar energy
3.9 kWh/m²
Travel score
6.3
out of 10

Saint-Jean-sur-Richelieu is city in Mobtérégie, Quebec, Canada.

Air quality
Good
PM2.5 7 µg/m³ · 2019
Density
419/km²
people per km²
Founded
2001

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 18°C by the end.

A typical September day in Saint-Jean-sur-Richelieu reaches about 21°C in the afternoon and slips back to 11°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 26°C. Set against its neighbours, September runs about 4°C cooler than August and about 8°C warmer than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
12313
22313
32313
42313
52313
62312
72212
82212
92212
102212
112212
122111
132111
142111
152111
162111
172010
182010
192010
202010
212010
221910
23199
24199
25199
26189
27189
28188
29178
30178

How September really feels in Saint-Jean-sur-Richelieu

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.

Saint-Jean-sur-Richelieu weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-4° / -13°7111.29.88.90.0
Feb-3° / -12°609.38.210.10.0
Mar / -6°7511.46.911.60.1
Apr11° / 9911.72.313.22.7
May19° / 104120.114.65.6
Jun24° / 14°11712.8015.46.3
Jul26° / 16°10713.3015.16.2
Aug25° / 15°10812.4013.96.5
Sep21° / 11°9810.7012.36.3
Oct13° / 11312.10.510.73.5
Nov / -1°8612.13.59.30.6
Dec-1° / -8°8312.59.28.60.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

Beyond those clear spells, partly cloudy skies cover about 18% 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 (%)
15149
25149
35248
45149
55149
65149
75149
85149
95050
105050
115050
125050
135050
145050
155050
165050
174951
184951
194852
204852
214852
224753
234654
244654
254555
264555
274456
284258
294258
304258

Chance of precipitation in September

Any precipitation

Saint-Jean-sur-Richelieu gets around 98 mm of rain over 10.7 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 36% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
135
235
335
436
536
636
736
836
937
1037
1136
1236
1336
1436
1536
1635
1735
1835
1935
2035
2135
2235
2335
2435
2536
2636
2736
2836
2936
3036

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 (%)
1402819121
2412818111
3432817111
4442817101
546271691
647271691
749271581
850271581
952261471
1053261470
1155251460
1256251360
1357241360
1459231350
1561221250
1661221250
1762211250
1865201140
1966191140
2067191040
2168181040
227017940
237216930
247316830
257415830
267714720
277813720
287913620
298012620
308311510

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
1911calm
2011calm
2111calm
2211calm
2311calm
2412calm
2512calm
2612calm
2712calm
2812calm
2912calm
3012calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 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 90 minutes over September. Sunrise moves from 5:19 AM to 5:56 AM, and sunset from 6:26 PM to 5:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:196:26
213.15:216:24
313.05:226:22
413.05:236:20
512.95:246:19
612.95:266:17
712.85:276:15
812.75:286:13
912.75:296:11
1012.65:306:09
1112.65:326:07
1212.55:336:05
1312.55:346:03
1412.45:356:01
1512.45:375:59
1612.35:385:57
1712.35:395:55
1812.25:415:53
1912.15:425:51
2012.15:435:49
2112.05:445:47
2212.05:465:45
2311.95:475:43
2411.95:485:41
2511.85:495:39
2611.85:515:37
2711.75:525:35
2811.75:535:33
2911.65:555:31
3011.65:565:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.9 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 July across the year — September's 3.9 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.6Bright
24.5Bright
34.5Bright
44.5Bright
54.4Bright
64.3Bright
74.3Bright
84.3Bright
94.2Bright
104.2Bright
114.1Bright
124.1Bright
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
263.4Moderate
273.3Moderate
283.3Moderate
293.2Moderate
303.1Moderate
Planning a trip in September

Is September a good time to visit Saint-Jean-sur-Richelieu?

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

6.3
Sightseeing
2nd-best month of the year
3.6
Beach & pool
4th-best month of the year

September is a reasonable time to visit Saint-Jean-sur-Richelieu for sightseeing.

What to pack for Saint-Jean-sur-Richelieu in September

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

In September, Saint-Jean-sur-Richelieu sees daytime highs around 21°C and nights near 11°C. Worth packing: rain gear. About 11 days see rain.

rain gear

UV index in Saint-Jean-sur-Richelieu 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 Saint-Jean-sur-Richelieu 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 December 22 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 8Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar3Moderate
Apr4Moderate
May6High
Jun6High
Jul8Very high
Aug3Moderate
Sep5High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Saint-Jean-sur-Richelieu?

Saint-Jean-sur-Richelieu sits at 45.3°N, 73.3°W, 32 m above sea level, in Canada. The nearest listed city is Chambly, 16 km away.

Topography around Saint-Jean-sur-Richelieu

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Saint-Jean-sur-Richelieu.

Within 3 km, the terrain around Saint-Jean-sur-Richelieu has only modest variations in elevation — a maximum elevation change of 42 m around an average of 36 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 275 m; within 80 km, large variations in elevation — a maximum elevation change of 1,181 m.

The land around Saint-Jean-sur-Richelieu is covered by artificial surfaces (41%) within 3 km, cropland (71%) within 16 km, and trees (47%) and cropland (35%) within 80 km.

3 km
42 m
16 km
275 m
80 km
1,181 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Chambly 16 km · Candiac 22 km · La Prairie 22 km · Brossard 22 km · Saint-Hubert 25 km · Saint-Constant 25 km · Saint-Basile-le-Grand 25 km · Greenfield Park 25 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 Saint-Jean-sur-Richelieu (45.3071°, -73.2626°, elevation 32 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).