"How's the weather today?"
This is a simple and direct way to ask about the weather in English. If you want a more polite version, you can say "Excuse me, what's the weather like today?" or "May I ask how the weather is today?"
The answer might be something like: "It's sunny with a high of 25 degrees Celsius." or "It's cloudy with a chance of rain."
If you want to know more about the weather, you can ask for specific information like the temperature, humidity, wind speed, etc.