What time of the year do landslides occur?

Landslides typically occur after periods of heavy rain, when the ground has become waterlogged and unable to hold together. However, landslides can also be triggered by mining, leaking water pipes, earthquakes and volcanic eruptions.

So, whatever time of year an area has heavy rainfall would be the time when landslides would be more likely to occur. In the United States, that would generally be in the spring - March through May.