Stanstead, Canada — Weather in September 2026

Monthly climate averages for Stanstead, Canada. Based on 10-year ERA5 reanalysis data.

Dfb Warm-Summer Continental
7.9 /10
Excellent

September is an excellent month in Stanstead

Climate Overview

Stanstead, Canada in September has mild conditions, with highs averaging 19.9°C (68°F) and noticeably cooler mornings.

This month falls at the beginning of Autumn.

Daily highs in September gradually drop from around 21°C (70°F) at the start to 18°C (65°F) by month's end.

September sees fairly even rainfall, totalling about 85 mm across the month.

Expect around 9.6h of sunshine at the start of September, decreasing to 8.4h by the end.

The warmest days tend to fall around the 5th, averaging 21.7°C (71°F).

Compared to August, this month is about 3°C cooler with 5 fewer rainy days. Temperatures begin dropping heading into October.

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Monthly September Averages

Temperature
20°C / 12°C
Feels Like
20°C / 11°C
Rain
9 days · 85 mm
Sunshine
8.9h / day
Humidity
79% — Humid
Wind
14 km/h
Wind Direction
SW (227°)
Gusts
34 km/h
Daylight
12.5 h
Cloud Cover
59%
Clear Sky Days
3.9
UV Index
4.9 — Moderate
Dew Point
12°C — Comfortable
Moon Phase
Waxing Crescent · 11%

Climate Charts

Daily averages based on historical data (2016–2025)

Daily Temperature

28°C 24°C 20°C 16°C 12°C 8°C 4°C 151015202530
HighLow

Daily Precipitation

0 mm 2 mm 4 mm 6 mm 8 mm 151015202530
Rainfall

Daily Sunshine

0h 3h 6h 9h 12h 151015202530
Sunshine

Daily Wind Speed

0 4 8 12 16 20 151015202530
Wind Speed
Sun Position
Sunrise 06:28
Daylight 12.6h
Sunset 19:02

Compare Months

January
Poor
Temp
-4°C / -12°C
Feels Like
-8°C / -17°C
Rain
14days (82 mm) Wet
Sun
4.9h Fair
Humidity
79% Humid
UV
1.8 Low
Snow Days
20days
View Details
February
Poor
Temp
-2°C / -11°C
Feels Like
-6°C / -16°C
Rain
13days (78 mm) Wet
Sun
6h Fair
Humidity
75% Muggy
UV
2.9 Moderate
Snow Days
18days
View Details
March
Poor
Temp
3°C / -6°C
Feels Like
-1°C / -11°C
Rain
14days (90 mm) Wet
Sun
7.1h Good
Humidity
72% Muggy
UV
3.8 Moderate
Snow Days
15days
View Details
April
Poor
Temp
10°C / 0°C
Feels Like
6°C / -4°C
Rain
15days (108 mm) Wet
Sun
7.9h Good
Humidity
70% Muggy
UV
4.9 Moderate
Snow Days
8days
View Details
May best
Good
Temp
17°C / 7°C
Feels Like
16°C / 5°C
Rain
13days (101 mm) Wet
Sun
9.6h Good
Humidity
71% Muggy
UV
5.4 High
Snow Days
1days
View Details
June best
Good
Temp
22°C / 13°C
Feels Like
22°C / 12°C
Rain
15days (129 mm) Wet
Sun
10.6h Excellent
Humidity
75% Muggy
UV
6.2 High
View Details
July best
Excellent
Temp
25°C / 16°C
Feels Like
26°C / 17°C
Rain
15days (126 mm) Wet
Sun
11.4h Excellent
Humidity
79% Humid
UV
6.8 High
View Details
August best
Excellent
Temp
23°C / 15°C
Feels Like
24°C / 15°C
Rain
14days (115 mm) Wet
Sun
10.5h Excellent
Humidity
79% Humid
UV
5.9 High
View Details
September best
Excellent
Temp
20°C / 12°C
Feels Like
20°C / 11°C
Rain
9days (85 mm) Wet
Sun
8.9h Good
Humidity
79% Humid
UV
4.9 Moderate
View Details
October
Fair
Temp
13°C / 6°C
Feels Like
11°C / 3°C
Rain
14days (125 mm) Wet
Sun
6.2h Fair
Humidity
79% Humid
UV
3.2 Moderate
Snow Days
2days
View Details
November
Poor
Temp
5°C / -2°C
Feels Like
1°C / -6°C
Rain
14days (99 mm) Wet
Sun
4.9h Fair
Humidity
79% Humid
UV
1.9 Low
Snow Days
13days
View Details
December
Poor
Temp
-1°C / -9°C
Feels Like
-5°C / -14°C
Rain
14days (95 mm) Wet
Sun
4.3h Fair
Humidity
78% Humid
UV
1.5 Low
Snow Days
19days
View Details
Month Temp Feels Like Rain Sun Humidity UV Status
January -4°C / -12°C -8°C / -17°C 14days (82 mm) Wet 4.9h Fair 79% Humid 1.8 Low Poor View Details
February -2°C / -11°C -6°C / -16°C 13days (78 mm) Wet 6h Fair 75% Muggy 2.9 Moderate Poor View Details
March 3°C / -6°C -1°C / -11°C 14days (90 mm) Wet 7.1h Good 72% Muggy 3.8 Moderate Poor View Details
April 10°C / 0°C 6°C / -4°C 15days (108 mm) Wet 7.9h Good 70% Muggy 4.9 Moderate Poor View Details
May best 17°C / 7°C 16°C / 5°C 13days (101 mm) Wet 9.6h Good 71% Muggy 5.4 High Good View Details
June best 22°C / 13°C 22°C / 12°C 15days (129 mm) Wet 10.6h Excellent 75% Muggy 6.2 High Good View Details
July best 25°C / 16°C 26°C / 17°C 15days (126 mm) Wet 11.4h Excellent 79% Humid 6.8 High Excellent View Details
August best 23°C / 15°C 24°C / 15°C 14days (115 mm) Wet 10.5h Excellent 79% Humid 5.9 High Excellent View Details
September best 20°C / 12°C 20°C / 11°C 9days (85 mm) Wet 8.9h Good 79% Humid 4.9 Moderate Excellent View Details
October 13°C / 6°C 11°C / 3°C 14days (125 mm) Wet 6.2h Fair 79% Humid 3.2 Moderate Fair View Details
November 5°C / -2°C 1°C / -6°C 14days (99 mm) Wet 4.9h Fair 79% Humid 1.9 Low Poor View Details
December -1°C / -9°C -5°C / -14°C 14days (95 mm) Wet 4.3h Fair 78% Humid 1.5 Low Poor View Details

What to Wear

Dress in layers — a mix of long sleeves, light sweaters, and a versatile jacket works best for changeable conditions.

A waterproof jacket or compact umbrella is recommended for occasional showers.

Packing List

Warm evening layerUmbrellaComfortable walking shoes

Frequently Asked Questions

September is typically excellent for visiting Stanstead, with average highs of 20°C (68°F) and around 9 rainy days. Stanstead, Canada in September has mild conditions, with highs averaging 19.9°C (68°F) and noticeably cooler mornings.
Stanstead typically sees around 9 rainy days in September with 85 mm (3.3 in) of total rainfall. An umbrella should suffice.
Nights in Stanstead during September are cool at around 12°C (53°F). Bring a jacket or sweater for evenings.
With highs of 20°C (68°F) and lows of 12°C (53°F) in September, we recommend: Warm evening layer, Umbrella, Comfortable walking shoes. Comfortable walking shoes are essential.
Yes, September offers some of the best weather conditions in Stanstead with comfortable temperatures and lower chances of rain.
The average UV index in Stanstead during September is 5 (moderate). Sunscreen and sunglasses are recommended during midday hours.
Stanstead gets approximately 13 hours of daylight per day in September, with around 9 hours of sunshine.
Snow is uncommon in Stanstead during September based on 10-year climate averages.

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