It's probably worth adding that there's no clear picture of what percentage impulse visitors add to the overall tourism during the season. An impulse visitor is one who, by definition, simply decided to "go out somewhere" in the morning, Up to, but not including, yesterday, there have been queues of vehicles on the A470 from the roundabout to Pydew down to Black Cat between 1630 and 1730. Yesterday was the first time I saw almost no queue, so impulse visitors were certainly down.
Although this group doesn't benefit the hotels that much, it does generally help Llandudno. Most have to eat, so cafes tend to do well, and in fact cafes are probably the most reliable indicators of visitor traffic overall. The other indicators are the old stalwarts: the Orme Trams - which still provide a unique experience - and possibly the Summit complex.
It is this group - impulse visitors, however, that seems most affected by grotty forecasts, as - if they have a day off to go out somewhere - the weather forecast is probably the determining factor about how that day should be spent. But it badly needs researching, so we can get some idea of the accuracy or otherwise of the surmise.