Scientists do not consider a hypothesis to be a fact. A hypothesis is defined as a possible explanation for something that can then be tested to see if it is indeed correct.
In science, you'll usually be dealing one of two different kinds of proposals:
1. Scientific Hypothesis
2. Working Hypothesis
They sound more complicated than you might think.
The Scientific Hypothesis basically just means you're giving a possible explanation for something that can test. For example, 'If you more than ten minutes of warm up before playing football, you will score more goals than if you warm up for less than ten minutes'.
A Working Hypothesis is slightly more complicated, in that you usually set out at the beginning by saying what you expect will happen before then going on to test what actually happens. But even if your initial hypothesis doesn't fit with your results, that's still okay. It was just a sort of early answer, to help guide you towards a working theory or fact.
If you're looking at formulating a hypothesis or hypotheses for your own research, then here's a pretty helpful video about forming them with some great examples taken from normal life: