A waterborne paint is water sensitive until it has dried (coalesced) and the water in the paint has evaporated completely, which takes longer at low temperatures and/or high humidity. (For example, in exterior applications, a FLUO TP Hydro paint will dry better in winter in dry and sunny weather, even if it is very cold, compared to the same application at 15°C but with 90% relative humidity); as long as the coalescence is not completely done, the film remains sensitive to water since it is its “solvent”. But when it is dry, it is dry! It’s like water-based façade paints, they are no longer sensitive to rain after drying. It can rain on an FLUO TP Hydro marking if it is dry. At room temperature and a humidity of about 65% FLUO TP and Fluo TP Hydro dry just as quickly (about 15 minutes).