Monthly Climate
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Best time to visit Longueuil

September is the best time to visit Longueuil for general sightseeing, with average highs of 21 °C and about 10 wet days. The comfortable season runs roughly May to September.

It depends what you are going for

One month rarely wins on everything. These are the best months on each measure taken on its own.

If you want Best month On that measure
Sightseeing and walking September comfort 87/100
The least cloud August 54 % average cloud cover
The least rain February 60 mm
Warmth July 26 °C
Cooler weather January -4.8 °C

Ranked by comfort

# Month Comfort / 100 Avg high Wet days
1 September 87 21 °C 10
2 June 85 24 °C 12
3 August 83 25 °C 12
4 July 79 26 °C 12
5 May 78 19 °C 12
6 October 57 13 °C 12
7 April 45 11 °C 11
8 February 28 -3.0 °C 9
9 March 27 2.8 °C 11
10 November 26 5.9 °C 12
11 January 26 -4.8 °C 11
12 December 24 -1.0 °C 12

When to think twice

December scores lowest with about 12 wet days and highs near -1.0 °C. That does not make it a bad month — it depends entirely on what you are travelling for. The numbers are all here; the judgement is yours.

The full year

Month Avg high Rainfall Cloud
January -4.8 °C 73 mm 68 %
February -3.0 °C 60 mm 64 %
March 2.8 °C 74 mm 64 %
April 11.0 °C 101 mm 65 %
May 18.8 °C 98 mm 62 %
June 23.7 °C 106 mm 61 %
July 25.9 °C 101 mm 55 %
August 24.8 °C 101 mm 54 %
September 20.7 °C 98 mm 55 %
October 13.2 °C 112 mm 63 %
November 5.9 °C 87 mm 70 %
December -1.0 °C 85 mm 71 %

Data sources and method

Normal period
1991–2020
Dataset version
era5-1991-2020-scores1.1
Last processed

Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: comfort score, beach score, season boundaries. Full formulas are on the methodology page.

Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.