"To fit the observations" means that a theory, explanation, or model is able to match or align with the evidence or data gathered from observations or experiments.
Sentences with «to fit the observations»
That description fits the observations of experts in other developed Western countries. (sciencemag.org)
This does not fit your observation that alcohol has a greater cooling effect than water, however. (scientificamerican.com)
At present there is no alternative hypothesis that fits the observations in front of us. (skepticalscience.com)