今日は良いお天気ですねって英語でなんて言うの？

It's lovely weather today. - This is just a statement about what good weather it is.
The weather is very fine today. - This is just another statement about the good weather
Isn't the weather lovely today? - This is a statement and a question too- you are asking the other person's opinion - it is a way of starting a conversation

Hope this helps
Jane :)

The first two examples are statements saying that on this day the weather is very good.
The last one is a very casual and consists of a statement and a question asking the listener to confirm your statement.

It is really nice to run into you. Lovely weather isn't it?
"isn't it" is a simple expression standing for "Is it not?"
For example: It's a lovely day, isn't it?
The person can respond by saying "Yes it is."

We often talk about the weather as being "out."
So we can say, "It's a bit rainy out today." Or, "It's been quite stormy out all week."
In order to engage more, we add, "Isn't it?"
This allows the other person to respond more comfortably.

Have a great day! :D

Nice day, isn't it? - This is an "opener" that sometimes use to approach a stranger. "Isn't it" is asking "is it not?" and it is a way to ask someone if they agree with you.

Lovely weather we're having today, am I right? - lovely is another way to say nice. You can add "am I right?" which is asking "do you agree with me?" to get a response from the other person.

All three of these expressions are simply statements. No conversation is necessary unless anyone wants to. A nod of the head or a smile is sufficient response. Or you may just like to agree: " Yes, what a wonderful day!"
1. To turn out = this phrase is used when talking about the development of the weather. "I hope it turns out sunny tomorrow. I want to go to the beach."
2. This is humorous. The word 'gay' was commonly used to mean bright, happy, colourful. However these days the word has been pretty well hijacked and is more closely connected with lesbians or homosexuals. How refreshing to use it in its original context!
3. This is a statement about the pleasant weather.

A perfect day for a swim /picnic hey?
A great way to start a conversation. The person will either agree
or suggest an activity of his own.
I'm loving this weather today!
The person will either agree or disagree and the
conversation will continue from there.

One of the biggest small talk topics is the weather topic, we use it to break the ice in many situations. Many of us share similar ideas and interests when it comes to the weather and so it makes for a light, easy conversation.
You can use the sentences above to talk about the weather.

This week the weather has been horrible, it has been raining non-stop creating flooded roads everywhere! How have you been coping?"
"Hey! How has the weather been treating you?"

Small talk: a conversation that is light and unimportant
Break the ice: make things feel more comfortable for people who are spending time with one another.

"Nice days isn't it?" and "good weather we're having"
these two expressions are used when greeting someone and bringing up the weather, as it is a very causal and well used conversation starter, as asking 'isn't it?' will make them reply then furthering the conversation fully.

all three of the above statements show your positive attitude towards the weather

Some day, ain't it?- In Ireland this means - Great day today, is it not?

What a day! Wouldn't you agree?

The weather has been amazing lately!

We've been blessed with this weather.

In Ireland we have perfected small talk. And the weather is a commonly talked about subject. :)

Both above are statements about the good weather.

If you see someone on the street and want to make small talk about the weather we would say something like "It's such a nice day huh" or "What a great day we're having!". These both say that the weather is very nice and that we are happy for the day we are having.