Connect to your favourite weather forecaster and look for the following conditions:
Category: Masonry Product: Masonry based weatherproofing coatings
Temperature Limitations: Use above +7 C (+45 F)
Rain Limitations: No rain until hardened -- about 8 hours
Wind Limitations: High wind can dry masonry products too rapidly
Humidity Limitations: Low humidity can dry masonry products too rapidly
Continuous Conditions: 72 hours keep moist and frost free
Comments: Masonry coatings must not freeze before they have cured at least three days. In fact they must be kept damp throughout this process, which requires more misting if the wind speed is high and/or the relative humidity is low. Once surface cured to prevent washing away (probably about 8 hours), rain will only help to keep the product moist. Freezing and drying are the enemies of all masonry products.
Weather limitations on most renovation products can be located on the WEATHER tab above.
APPLICATION / INSTALLATION DETAILS
Pargings, like stucco, on the outside of the house are not "waterproof" coatings but "weatherproof" coatings -- an important distinction.
Like most sidings they are designed to shed rain, protect the wall from mechanical damage and the UV rays of the sun.
Like most sidings they must allow moisture to escape from the wall and in the case of stucco that is by having a material that is quite permeable.
Waterproof stucco, or efforts at total face seals on the outside of the house, generally cause moisture and rot problems in the Canadian climate.
Many of the tips for WORKING WITH MORTAR IN HOT & COLD WEATHER apply to stucco as well.
Don't miss the reasoning behind the warning: NEVER ADD SOAP TO A STUCCO MIXTURE.