In this part of the world, we’re used to experiencing four seasons in one day. This can mean that the perfect painting day can be impossible to predict or control. The good news is there’s a wide variety of Resene products that can help you adapt as conditions change. 

The perfect painting day

If the stars – and sun and clouds ‒ align, the perfect painting day would be 15-20°C with humidity of 70-80% and a very gentle breeze. Another way to look out for the perfect painting day is to ask yourself: “Does the weather pass the washing line test?” If your clothes aren’t drying on the washing line, your paint won’t dry on the walls. Another test to try is applying a thin coat of water to a piece of timber, if the water has not evaporated in 15 minutes, hold off on painting until it does. 

How to paint in hot sunny weather

A hot sunny day might seem like the ideal time to paint, but in fact it can make painting and staining quite tricky as the paint can dry too quickly. When paint is drying too quickly, it can be difficult to maintain a wet edge. Maintaining a wet edge means making sure the edge of your paint brushstrokes stay wet and don’t dry out before the next stroke is applied. Wet edge painting avoids lap marks and streaks, creating a better end result. 

Adding Resene Hot Weather Additive to exterior paints such as Resene Lumbersider Low Sheen, or interior paints such as Resene SpaceCote, will prevent your paint from drying too quickly in hot weather, making it easier to maintain a wet edge. Resene Hot Weather Additive can also be used alongside Resene FX Paint Effects Medium if you are creating a two-tone look or limewashed effect.

If you can’t avoid painting your exterior in the height of summer, start painting on the shady side of the house and try to stay ahead of the sun. Remember, painting your home exterior is a big investment in time and effort and choosing a cheap and poor-quality paint is a false economy, especially with our UV light levels. Resene waterborne paints are built to withstand UV degradation and will last much longer than cheap paints. Some paint colours, such as bright organic reds like Resene Red Berry and yellows such as Resene Wild Thing, are more vulnerable to fading caused by UV radiation – for these colours, a final coat of Resene Clearcoat UVS, which contains UV inhibitors, will help maintain the colour’s vibrancy.

A note on wallpapering

Some wallpapers, especially paper-based designs, can shrink in hot weather if not handled with care. Wallpaper should be left to dry in a well-ventilated room. If the room is very hot, you may need to use a fan (or heat pump set to cool) to keep the room at a stable temperature. Never turn the heater on while wallpaper is drying.

How to paint in cold temperatures

As a rule, paint won’t dry if the temperature is lower than 10°C. This is because the particles that make up the waterborne paint binder harden in the cold and they can’t fuse together to form a film. The Resene Wintergrade range has been designed by the Resene technical team to allow you to paint in temperatures as low as 3°C. 

Resene Wintergrade Additive can be added to selected Resene waterborne paints, allowing them to be applied in lower temperatures. If you’re painting indoors, look out for “crying windows” where condensation drips down the glass, making the paint drying process even more difficult. Keep the temperature inside your home around 15-16°C using a heater or heat pump, but make sure the room is ventilated to help the paint to cure.

How to paint in humid or rainy conditions

Although it’s best to avoid painting in medium or heavy rain, a few light drops don’t need to dampen your spirits. If you’re painting on a day where a light shower may randomly occur, use Resene Umbrella Additive. This product adds a protective layer to your paint so light drops will roll off the surface – even on paint that hasn’t fully dried!  It’s not designed for rain or heavy squalls – on those days it’s best to paint indoors instead or focus on prep work. 

It’s worth noting that Resene’s high-quality paint binders are flexible, and designed to bend when wood or other substrates expand and contract in wet and dry conditions, meaning your paint will keep looking good for longer.

How to paint in changing humidity and spring and autumn

As waterborne paint dries when water evaporates from it, it’s not surprising that changes in humidity and temperature can wreak havoc on the drying process. When air is saturated by water it has 100% relative humidity, and at this point the air cannot hold any more water (in a gas form). Air can only hold a specific amount of water at certain temperatures. At 15°C, for example, one cubic metre of air can hold exactly 12.8gm of water vapour and no more. If you’re trying to dry paint in these conditions it won’t work, as there is no ‘room’ in the air for the water particles evaporating from the paint. If you think of those humid summer days where water drips down the outside of your cold glass of water, this is the same effect.  There is so much water already in the air that the water on your glass can’t evaporate, so instead you end up with a dripping glass.

In spring and autumn painters should be aware of sudden drops in temperature and rising humidity in the afternoon, which can cause water to condense and form dew (called the ‘dew point’). Between 70-80% humidity is the ideal humidity level for painting.

To make the most of your project time, plan to have a few jobs you can do no matter what the weather is. For example, have a prep project you can do when it’s raining, an exterior staining or painting project when the weather is dry and an inside project when it is too dark to do work outdoors. That way you can keep progressing your DIY no matter what the weather is doing.

Our changeable climate means we need to be prepared for every temperature, humidity and rain scenario – but whatever the weather conditions, Resene has you covered.

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