Frozen pipes will start to thaw at 20 degrees celsius.
If you have water pipes that are exposed to temperatures of 20 degrees celsius or less, such as exterior hose bibs in the winter, you should turn the water off to those faucets and then open the faucets to drain any water.
To help prevent pipes from freezing you can wrap them in insulation. There are numerous pipe insulation products available. Visit your your local hardware store to learn more.
Assuming a temperature of 20 degrees celsius or less, and the water pipe is not in use, it will take approximately 4 to 5 hours for a water pipe to freeze and burst.
Thawing a frozen water pipe can take 30 to 45 minutes. If you have a frozen pipe, contact a local plumber immediately. When water turns into ice it expands which can cause pipes to crack and burst which will lead to water damage if not addressed in a timely manner.