The weather forecast is a good example. temperature is an objective truth, when the weather lady says the humidity and temperature outside, direction of the wind. This is all objectively true to the question, "what is the weather".
However when the we she tells you the forecast, that is more of a speculative truth that is subject to her knowledge and study done on the weather patterns, the forecast may be true, but its not speaking to an objective that is clearly defined by a question.
I am actually just learning about this myself, there is 2 kinds of news. Journalists and Pundits. Journalists talk about facts, pundits share their opinion.
Fact can be used to answer questions directly.
Opinion can only be used to speculate.