Sea Fret / Haar are both forms of sea fog.. The sort of stuff we get in early summer, as warm air passes over the still cold Channel waters. Anything at the moment won't be sea fog as the temps are the wrong way round.
The 95% humidity would be a concern. As air cools, its ability to hold moisture in vapour form decreases, so 95% humidity at 4C, would possibly generate fog at 3C. It would depend on the dew point.
Parts of Lewes are ideal for fog though.
Low lying area in a bowl - check
surrounded by hills for colder air to katabatic winds to flow down - check
near a river as a source of moisture - check
clear night - radiative cooling of the ground and bingo.
Falmer is also in a low point, but I...
The forecast conditions aren't quite as 'safe' as they looked yesterday. There will be fog in places tonight. We have to hope that Falmer and particularly the stadium site aren't prone to advection fog.
I think the risk of fog will have decreased by Tuesday night, as we pick up more cloud and slightly more breeze. That's my take on it anyway. I'll re-visit it tomorrow.