You can do anything you want, I wont write it for you but I have given you all the bits you need.
There are TTS recipes here in these fora
being one good place to start, (kudos to @lgaetz )
edit: OOPS, that’s speech to text but the recipe is still basically good for text to speech
TTS sounds ‘natural’, is mostly free for small volumes and will save you a lot of RTFM’s.
You could cronjob it every 12 hours (completely outside any asterisk/dialplan integration) and have a prebuilt .wav file ready for your location and easily added to your dialplan without ever going over your monthly free allowance of 500 minutes
I’m just not understanding your reticence to try it.
paste
This Afternoon, the forecast is A slight chance of rain showers between 1pm and 2pm, then a slight chance of showers and thunderstorms between 2pm and 4pm. Mostly sunny, with a high near 64. West northwest wind around 18 mph, with gusts as high as 26 mph. New rainfall amounts less than a tenth of an inch possible.--Tonight, the forecast is Mostly clear, with a low around 41. North northeast wind 8 to 16 mph, with gusts as high as 23 mph.--Sunday, the forecast is Sunny, with a high near 70. East wind 5 to 9 mph.--Sunday Night, the forecast is Mostly clear, with a low around 43. East southeast wind 7 to 10 mph.--Monday, the forecast is Sunny, with a high near 79. South wind 7 to 12 mph.
into
https://www.ibm.com/demos/live/tts-demo/self-service/home
to hear what it would sound like