under the weather
Sentirse o estar under the weather es sentirse o estar enfermo

Paul has gone to bed because he’s feeling a bit under the weather.
I’m feeling under the weather – I think I’ve caught Jonh’s cold.

a fair-weather friend
un amigo que solo es tu amigo cuando todo va bien, pero desaparece cuando tienes problemas

When I lost my job and my home he didn’t want to see me: he was a fair-weather friend.

as right as rain
Sentirse perfectamente de nuevo.
I don’t feel well but I’m sure I’ll be as right as rain for tomorrow’s meeting.

He had an operation on his back las month; but he’s as right as rain now.

raining cats and dogs
llover mucho

Don’t forget your umbrella: it’s raining cats and dogs!

Come rain or shine
pase lo que pase

I’ll be there for you, come rain or shiine.

bucket down
Diluviar

It’s bucketing down; don’t forget your umbrella.

take a rain check (on something)
Posponer algo

Can I take a rain check on our dinner date? I have to work late tonight.

Save for a rainy day
Ahorrar dinero para futuros imprevistos

I’m saving 50 € a month for a rainy day.

it never rains but it pours
Similar a la expresión española, las malas noticias nunca vienen solas.

I’ve had a horrible week. First I locket myself out of my house, then my car broke down, and today I fell over on my way to work. It never rains but it pours!

Snowed under
tener demasiado trabajo

Shes is totally snowed under at wordk
We are snowed under at word because two members of staff are on holiday

break the ice
Como en castellano Romper el hielo

We played party games to help break the ice!

Put on ice
Posponer algo

The new housing development has been put on ice because the building company are bankrupt. A new company will take over in six months time.

The tip of the iceberg
La punta del iceberg

I’ve tidied the kitchen but it’s just the tip of the iceberg – the rest of the house is a mess.

under a cloud
si alguien está under a cloud, está bajo sospecha de algo

She left the company under a cloud after some money went missing.

on cloud nine
estar muy muy muy feliz

He was on cloud nine after she agreed to marry him

Every cloud has a silver lining
Significa que algo bueno sucede siempre después de algo malo.

I lost my job las week, but every cloud has a silver lining and now I have time to visit my family in Australia!