Painting by numbers is one of the most relaxing hobbies you can enjoy at home, but very hot weather can make it a little more challenging. When the temperature rises, acrylic paints can dry faster, thicken in the pots, drag on the canvas, and become harder to blend or spread neatly. The canvas itself can also feel different, especially if the room is warm, dry, or in direct sunlight. As this Sumer heads to be a record breaking one, use the top tips to stay in control of your painting.
The good news is that hot weather does not have to spoil your painting experience. With a few simple changes to how you store your paints, prepare your canvas, and work through your kit, you can keep the paint flowing smoothly and achieve a clean, colourful finish.
This guide looks at the best ways to do painting by numbers in very hot weather, with a focus on maintaining paint quality and keeping a good flow on the canvas.
Keep Your Paints Out of Direct Sunlight
The most important rule is simple: never leave your paint pots in direct sunlight. Acrylic paint is water-based, which means heat can cause moisture to evaporate quickly. Once that happens, the paint can become thicker, stickier, and harder to apply.
Even if the paint pot is closed, strong sunlight can still warm it up. This may affect the texture of the paint and make it less pleasant to use. Ideally, keep your paint pots in a cool, shaded place before and during painting.
A drawer, cupboard, storage box, or shaded table is usually enough. Avoid leaving your paints on windowsills, conservatory tables, garden furniture, or anywhere the sun moves across during the day. Paints may look fine at first, but after a few hours of heat they can start to dry around the edges or lids.
Paint During the Coolest Part of the Day
In very hot weather, timing makes a big difference. Try painting early in the morning or later in the evening when the room is cooler. This helps slow down drying time and makes the paint easier to control.
Midday and early afternoon are often the worst times to paint, especially in rooms that catch the sun. Paint may dry on the brush before you have finished filling a section. It may also dry unevenly on the canvas, leaving streaks or patchy areas.
A cooler room gives you more working time. The paint stays smoother for longer, and your brush glides more easily across the canvas. This is especially useful when working on larger numbered areas or lighter colours that need a clean, even finish.
Use a Small Amount of Paint at a Time
When it is hot, only open the paint pot you are using. It can be tempting to open several colours at once, especially when working through a detailed area, but this increases the risk of drying.
Open one pot, use it, then close it properly before moving to the next colour. If you need to use the same colour repeatedly, still try to close the lid between sections. It only takes a few seconds, but it can help preserve the paint.
Make sure the lid clicks or seals fully. Dried paint around the rim can prevent the lid from closing properly, so wipe the edge of the pot if needed. A clean seal keeps the moisture inside and protects the paint for future sessions.
Add Tiny Amounts of Water When Needed
If your acrylic paint starts to feel thick, do not panic. In many cases, you can improve the flow by adding a very small amount of clean water.
The key is to add water gradually. Use the tip of your brush, a cocktail stick, or a dropper if you have one. Add one tiny drop, mix well, and check the texture. You want the paint to become smooth and creamy, not watery.
Too much water can reduce coverage and make the colour look weak. It can also cause the paint to spread beyond the printed lines on the canvas. This is why patience matters. Add less than you think you need, mix thoroughly, then add a little more only if necessary.
For painting by numbers, the ideal texture is usually similar to single cream. It should move easily from the brush but still cover the number and printed lines underneath.
Keep a Damp Brush, Not a Wet Brush
In hot weather, your brush may dry quickly while you are painting. This can make the bristles stiff and cause the paint to drag across the canvas.
Keep a small cup of clean water beside you and rinse your brush often. After rinsing, blot the brush gently on kitchen roll or a cloth. The brush should be damp, not dripping.
A brush that is too wet can thin the paint too much and make it harder to stay inside the lines. A dry brush, on the other hand, can create scratchy marks and uneven coverage. A lightly damp brush gives the best balance. It helps the paint flow smoothly without flooding the canvas.
Avoid Painting in Front of a Fan
A fan may make you feel cooler, but it can cause problems for acrylic paint. Moving air speeds up drying, both in the paint pot and on the brush. It can also dry the surface of the paint before you have had time to smooth it out.
If you need a fan, angle it away from your painting area. Let it cool the room rather than blow directly across your canvas or paint pots.
The same applies to open windows on a breezy day. Fresh air is helpful, but strong airflow can make paint dry faster than expected. A calm, shaded, well-ventilated room is better than a windy one.
Work in Smaller Sections
Hot weather is not the best time to cover large areas in one go. Paint can start drying before you have finished smoothing the section, which may leave visible brush marks.
Instead, work in smaller sections. Complete one area neatly, then move on. If you are painting a large background, divide it mentally into smaller parts and keep your brush strokes consistent.
This approach helps maintain a wet edge for longer. It also gives you more control over coverage and reduces the chance of patchiness.
Use Thin Layers Rather Than Thick Blobs
When paint starts drying quickly, some people try to solve the problem by loading the brush with more paint. This can lead to thick blobs, raised edges, and uneven texture.
A better method is to use thin, smooth layers. Apply the first layer neatly, let it dry, then add a second coat if needed. This is especially useful with pale colours, yellows, whites, creams, and light blues, which may not cover printed numbers fully in one coat.
Thin layers usually look cleaner than one heavy layer. They also reduce the risk of cracking or clumping in hot weather.
Keep the Canvas Cool and Flat
Heat can affect the canvas too. If your painting by numbers canvas becomes warm, curled, or slightly loose, it may be harder to paint accurately.
Before you start, place the canvas on a flat surface away from direct sunlight. If it has been stored in a hot room, let it cool down first. You can tape the corners to a board or table to keep it steady.
A stable canvas helps the brush move more smoothly. It also stops paint gathering in tiny dips or raised areas.
Take Short Breaks and Close Everything
Hot weather can make painting tiring, especially if you are concentrating on small details. Taking short breaks is sensible, but always close your paint pots before you step away.
Even a five-minute break can allow paint to dry around the rim or thicken on the surface. Rinse your brush, close the paint pot, and cover your canvas if dust or insects are a problem.
This simple habit keeps your materials in good condition and makes it easier to return to the painting later.
Store Paint Pots Carefully Between Sessions
After painting, check that every pot is firmly closed. Store the paints somewhere cool and shaded. Avoid sheds, cars, windowsills, loft rooms, or conservatories during hot weather, as these places can become much warmer than the rest of the home.
If you are working on a kit over several weeks, good storage is essential. Acrylic paint can last well when sealed properly, but heat and air exposure are its biggest enemies.
You can also place the paint pots in a small airtight container or resealable bag for extra protection. This helps reduce moisture loss and keeps the paints together.
Clean the Pot Rims
Paint often gathers around the rim of small paint pots. In warm weather, this can dry quickly and stop the lid from sealing. Once the seal is poor, the paint inside may dry faster.
Use a damp cloth or tissue to clean the rim before closing the pot. You do not need to do this every single time, but it is worth checking regularly, especially with colours you use often.
A clean rim means a tighter lid. A tighter lid means better paint.
Keep Your Hands Cool and Dry
Hot hands can make painting less comfortable. Sweat or moisture from your hands may also mark the canvas, especially in unpainted areas.
Try resting your hand on a clean sheet of paper while painting. This protects the canvas and helps your hand glide more easily. It is particularly useful when working on detailed sections.
You can also wash and dry your hands before painting, or keep a soft cloth nearby. Comfort matters. The more comfortable you are, the more controlled your brushwork will be.
Final Thoughts
Painting by numbers in very hot weather is all about controlling heat, air, and moisture. Keep your paints cool, open only one pot at a time, add tiny amounts of water when needed, and avoid direct sunlight or strong airflow. Work in smaller sections, use thin layers, and keep your brush damp rather than wet.
With these simple habits, your paint will stay smoother, your brush will move more easily, and your finished canvas will look cleaner and more vibrant.
Hot weather may change how you paint, but it does not have to stop you. Choose a cool corner, take your time, and enjoy the process.
