It depends on the product. The data sheet for Benjamin Moore’s Aura Exterior paint allows it to go on from 4.4 °C, while an oil stain such as Arborcoat needs at least 10 °C. For a deck, CAA-Québec recommends 10 to 32 °C for 24 hours, with no rain, dew or frost forecast for three days.
By the DV Groupe team · Updated · 2 min read
01
Two products, two thresholds
The minimum temperature comes from each product’s data sheet. Two examples from Benjamin Moore:
4.4 °Cminimum, Aura ExteriorSurface temperature at application; maximum 37.7 °C.
10 °Cminimum, Arborcoat stainSurface temperature at application; maximum 32 °C.
1 hdry to the touch, AuraAt 25 °C and 50 % relative humidity.
4 hbefore a second coat, AuraUnder the same conditions.
Source: Benjamin Moore, data sheets K629 and K328
02
Reading the data sheet
Every paint and every stain has a technical data sheet. It gives the minimum and maximum application temperature, measured at the surface, and the drying times, given at 25 °C and 50 % relative humidity.
Both sheets cited here say the same thing about the cold: high humidity or cold temperatures lengthen drying and the wait before a second coat. Painting near the minimum is allowed, but everything takes longer.
03
Before painting outdoors
The surface temperature
It has to sit within the product’s range, not just the air.
The days that follow
For a deck, CAA-Québec asks for three days with no rain, dew or frost in the forecast.
A dry surface
For deck wood, CAA-Québec sets the maximum at 15 % moisture.
The sun
For a deck, CAA-Québec advises a cloudy day rather than hot, sunny weather.
04
What about a deck?
CAA-Québec’s range for a deck, between 10 and 32 °C for 24 hours, covers paint and stain alike. The waiting times are in When to stain a wood deck, and DV Groupe’s exterior painting is scheduled around the data sheet of the product chosen.
Common questions
Can you paint outside in October?
Yes, if the surface temperature meets the product’s minimum, for example 4.4 °C for Aura Exterior or 10 °C for a stain such as Arborcoat, and the weather stays dry.
How long does exterior paint take to dry?
For Aura Exterior, one hour to the touch and four hours before a second coat, at 25 °C and 50 % relative humidity. In cold or damp weather it takes longer.
Can you paint in full sun?
The data sheets also set a maximum surface temperature: 37.7 °C for Aura Exterior and 32 °C for Arborcoat. For a deck, CAA-Québec advises a cloudy day.
