MONTREAL - Montreal's mayor is advising people to postpone their Halloween trick-or-treating until Friday with record rainfalls in the forecast.

A rainfall warning is in place for the Montreal area, with 40-50 millimetres of rain expected. The record rain for Halloween was in 2013, when 22.4 millimetres of rain fell in the region. Those conditions could bring on flash flooding and ponding on roads, Environment Canada warns.

Montreal joins Longueuil, Varennes, McMasterville, Sorel-Tracy, Mont-Saint-Hilaire, Beloeil, Magog and Candiac, among the other municipalities who are postponing Halloween until Friday due to the weather forecast for Thursday.

Montreal West officials said they are not issuing any notice suggesting trick-or-treaters postpone going door-to-door. Laval says it is not postponing its activities planned for Oct. 31, but will have police presence in residential neighbourhoods on Friday, in case trick-or-treaters delay a day.

The city of Sainte-Julie kicked off the trend Wednesday morning by officially asking its residents to delay Halloween activities by a day in order to avoid having trick-or-treaters head out during the heavy rains and strong winds forecast for Thursday.

The mayor of Sainte-Julie - a city of about 30,000 located southwest of Montreal - cited exceptional weather conditions as the reason for the postponement. (The city says it is expecting at least 40 mm of rain tomorrow and very strong winds).

"Taking into account the safety and comfort of the children and adolescents who would like to take to the streets to collect candy, we have decided to take the exceptional step of postponing (Halloween) until Friday," Sainte-Julie Mayor Suzanne Roy said in a statement. "Normally rain would not have made us change the date, but the exceptional nature of the precipitation pushed us to do it."

The city says it will communicate with its residents regularly in the coming days to update them on the status of Halloween events in the city and advise on safety precautions to be taken.

Earlier Wednesday, Environment Canada had issued special weather statements that warned of torrential rain and blustery winds in the Montreal area, as well as snow in more northerly parts of Quebec.

So many cities have postponed Halloween festivities that some - such as Sherbrooke in the Eastern Townships  - have issued releases saying Halloween will actually proceed as scheduled on Oct. 31.