OPTION A (in MLA style): The wWeather in Shanghai Today¶
OPTION B (in APA style): The weather in Shanghai today

ALSO POSSIBLE: It’s sunny, but a litslightley cloudy here today.

SMOOTHER: The temperature ishas risen up to 19℃.

However, it’OPTION A: However, weather reports saying that it will be down to zero next week.¶
OPTION B: However, it is said that temperatures will reach zero next week.

The wWeather in Shanghai Today

Alternatively, you could un-capitalize both “weather” and “today.”

The temperature is up to 19℃.

Suggestions:
• It’s supposed to get up to 19°C.
• It got up to 19°C.
• The high is expected to be 19°C.
• The high was 19°C.
All of the above mean “今天的最高气温是19度”, but if you want to say that this temperature seemed warm to you, like “今天气温高到19°C”, then you could say “today’s high was/will be a balmy 19°C.” Adding an adjective like “balmy” tells the reader that this temperature seemed warm to you.

Note: I didn’t include the word “temperature” in my examples because it’s implied in “19°C” and, therefore, we would typically omit it from a sentence like this.

The wWeather in Shanghai Today

It’s sunny, but a little cloudy here today.

The wWeather in Shanghai Today

The wWeather in Shanghai Today