The solution, possibly surprisingly, is the fact that your opening line is truly not so essential, and all sorts of this striving for originality and wit is an effort that is wasted. The truth is conversational ‘openers’ are seldom original, elegant or witty, and no-one expects them become therefore. The greatest ‘openers’ are, basically, those that can certainly be recognised as ‘openers’ – as tries to begin a discussion.
The standard Uk touch upon the current weather (“Nice day, is not it?” or “Doesn’t feel just like summer time, eh?”, etc.) is going to do fine, as everyone understands it is a conversation-starter. The fact these responses are phrased as concerns, or having an increasing ‘interrogative’ intonation, does not always mean that the presenter is not sure in regards to the quality regarding the weather and needs confirmation: it indicates that a response is being invited by the speaker in purchase to start out a discussion. Okumaya devam et