When someone says it never rains but it pours, they mean problems don't just happen occasionally - they happen all at the same time.

Examples:

We had nothing to do for weeks, then suddenly we have all this work to do: it never rains but it pours!

I missed my train this morning, lost my wallet and spilt coffee all over myself. It never rains but it pours.

Take note

If you pour cold water on someone's plans or ideas, you are criticising or being negative about them.

Example:

I wanted to walk up the mountain but Jane threw cold water on the idea. She insisted on taking the cable car.