How long does exterior paint need to stay dry before rain?
Latex exterior paint needs from 1 hour to at least 4 hours without rain, and oil-based paint from 6 to at least 8, depending on the product and the weather. Behr says its Ultra Exterior Flat can resist rain after 60 minutes and Sherwin-Williams says most products need 4 hours or more [1][3]; Teknos rates its Teknolin oil paint rain proof after 6 hours at 73°F (23°C) and 50% relative humidity, and Sherwin-Williams asks 8 or more for oil paint above 70°F (21°C) [3][4]. Cool, damp weather slows drying, and overnight dew can damage wet paint just as rain can [4][5][6].
Rain-free times by product
Each maker tests its own paint, so check the data sheet for the can you buy.
- Behr Ultra Exterior Flat (100% acrylic): resists rain as early as 60 minutes after application, yet the same data sheet says to avoid painting if rain or snow is expected within 2 to 3 hours [1].
- Sherwin-Williams Resilience (latex): resists moisture in two hours [2]. For most products, Sherwin-Williams advises at least 4 hours of dry time before moisture can settle [3].
- Benjamin Moore Aura Exterior Soft Gloss (100% acrylic): dry to the touch in 1 hour and ready for a second coat in 4 hours at 77°F (25°C) and 50% relative humidity. The data sheet gives no rain-free time [5].
- Teknos Teknolin (alkyd-oil): rain proof after 6 hours at 73°F (23°C) and 50% relative humidity, and ready for a second coat after 1 to 3 days [4].
- Oil-based paint in general: Sherwin-Williams advises at least 8 hours above 70°F (21°C), and longer when it is cooler [3].
- Dulux Weathershield Gloss (Australia): no rain-free time in hours, but rain or overnight dew while it dries may damage or remove it [6].
Where a sheet gives two figures, plan around the longer one: for Behr, its own 2 to 3 hours [1].
What makes paint take longer
Makers' dry times, where conditions are given, are for mild weather: 73 to 77°F (23 to 25°C) at 50% relative humidity [1][4][5]. Cooler or damper air slows drying: Benjamin Moore says high humidity and cool temperatures lengthen dry and recoat times [5], Behr says dry times depend on temperature, humidity and how thick the coat is [1], and Teknos says drying is slower in cold or damp [4].
Makers also set limits on the weather while you paint and while the paint dries:
- Behr Ultra Exterior Flat: air and surface between 35 and 90°F (2 and 32°C), at least 5°F (about 3°C) above the dew point, and not dropping below 35°F (2°C) within 48 hours [1].
- Benjamin Moore Aura Exterior Soft Gloss: surface between 35 and 100°F (2 and 38°C) while you paint [5].
- Teknos Teknolin: air, surface and paint above 41°F (5°C), and relative humidity below 80%, while you paint and while it dries [4].
Sherwin-Williams gives 50°F (10°C) as the normal minimum for latex and says traditional latex needs more than 60°F (16°C) to cure properly; its low-temperature paints cure down to 35°F (2°C) [3].
Dew counts too
Dew forms on almost everything once the sun goes down, Sherwin-Williams notes. After a warm day and a cool night, fresh latex can stop forming a film, and moisture that gets in can stain the surface and weaken adhesion [3].
Purdue Extension advises against painting in the evening on cool spring and fall days, when heavy dew forms before the paint has dried: dew can wrinkle oil paint or dull its gloss, and streak latex [7].
Sherwin-Williams suggests keeping the paint above the dew point for at least 48 hours where you can, and stopping earlier in the day the cooler it gets [3]. Dulux says to stop early enough on cold days for the paint to dry before evening [6].
How Fairspell's Paint the fence template handles this
Fairspell is an iPhone app that searches the hourly forecast for a run of hours that suits an activity. Its Paint the fence template looks for:
- At least 4 hours in a row to paint.
- 4 dry hours before the window and 8 dry hours after it. An hour counts as wet when the forecast shows 0.3 mm (about 0.01 in) of rain or more, and Fairspell trims or drops a window that fails the check. If the forecast ends before those hours, the window stays and is marked Not confirmable yet.
- No hour in the window with more than 0.2 mm (0.008 in) of rain forecast.
- A higher score when rain chance is 0 to 5%, temperature is 54 to 75°F (12 to 24°C), wind is 0 to 9 mph (0 to 15 km/h) and humidity is 30 to 70%.
Eight dry hours is longer than the latex (water-based) times above and matches Sherwin-Williams' minimum for oil paint above 70°F (21°C). If your paint's data sheet gives a different time, open the activity and change Dry after under Rain safety; it goes from 0 to 24 hours. The template reads forecast rain, not dew, so on a cool evening stop early anyway.
Paint the fence is one of the templates in the free version, which allows two activities and a three-day forecast. Fairspell Full, a one-time purchase ($7.99 in the US), adds unlimited activities and a ten-day forecast. Forecasts change, so a window is guidance, not a guarantee.
Sources
- BEHR ULTRA Exterior Flat Paint No. 4850, Technical Data Sheet, Behr Process Corporation, accessed 2026-10-16
- Resilience Premium Exterior Paint, Sherwin-Williams, accessed 2026-10-16
- Exterior: Product Application Frequently Asked Questions, Sherwin-Williams, accessed 2026-10-16
- TEKNOLIN oil paint, Data Sheet 744, Teknos, accessed 2026-10-16
- Aura Waterborne Exterior Soft Gloss N632, Technical Data Sheet, Benjamin Moore, accessed 2026-10-16
- Weathershield Gloss, Dulux Australia, accessed 2026-10-16
- Selection and Application of Exterior Finishes for Wood (NCR-135), Purdue University Cooperative Extension Service, accessed 2026-10-16
Published 2026-10-16. Updated 2026-10-16.