You'd better take an umbrella with because it has many rainy days

You'd better take an umbrella with you because it has many rainy days.
You'd better take an umbrella with youin case it should rain.

with you,
It is rainy these days.

You'd better take an umbrella because it has many rainy days

You'd better take an umbrella with you because there are many rainy days.

我觉得应该是：
You'd better take an umbrella with you because it has been rainy these days.

You'd better take an umbrella with you, because it has rained many days.