Here's my recommended re-write.. (made 2 paragraphs to make this more readable with the changes..)

For 2 months it has been raining at least 4 times a week. I am surprised why it is rainy every weekend, probably it doesn't like we have much fun on weekend. Why am I surprised that every weekend is also rainy, when it seems the weather doen't want us to have fun even on the weekend! (This seems like the general idea you're trying to express..) 

Furthermore (a bit too formal here, I think) Also, the sky is often cloudy and dismal. (dippersful - not sure what you were trying to say here, so I used a typical word that people associate with a cloudy sky..) Despite of it is not a very pleasant, In spite of this at least it the rain causes the summer temperatures to comes down in summer.

rainy weather

It has been raining since 2 months ago at least 4 days each week. I am surprised why it is rainy every weekend, probably it doesn't like we have much fun on weekend. Furthermore the sky is often cloudy and dippersful. Despite of it is not a very pleasant, at least it causes the temperature comes down in summer.