"Oh it's sunny today" doesn't imply anything about the area it is supposedly describing, so it's not an overgeneralization in any way.
"If you had worn masks or started being cautious before COVID" you wouldn't be catastrophizing, because the identifying symbol of catastrophizing is concluding with high confidence a catastrophe from limited or contradictory evidence. We had plenty of evidence for pandemics (and most epidemiologists saw this coming for decades).
I believe you might be confusing cognitive distortions with heuristics (which are similar, but not the same).
Cognitive distortions correspond to irrational thought patterns or lines of reasoning.
If you have limited information, by example, you're not supposed to just jump to a conclusion (except in a matter which requires immediate response), and this is often seen in many mental health disorders where, by example, a person may jump to conclusions such as "everyone hates me" or "I'm screwed for life" from isolated events which predict no such overarching conclusion.
Those kinds of cognitive distortions are not the only tools we have to reason about anything in the presence of limited information, we can often do much better, which is why it's used on CBT.