A portable indoor and outdoor evaporative cooling unit includes a conduit structure with an inlet and outlet, an air blower, and a plurality of nozzles for emitting water or other evaporating coolant into the air flow. The nozzles connect to a source of water or the like and are positioned in or on the conduit such that sprayed coolant mixes together with the forced air to form a mixture whose temperature drops via evaporative cooling. The outlet directs the mixture in streams or clouds where persons can immerse themselves or walk through to cool down. Alternative embodiments include an inverted L-shape, a tower and a framework forming a pavilion. One or more porous membranes can be placed along the flow path, particularly at the outlet, with at least one nozzle arranged to soak the membrane. As used at the outlet, the membrane forms a flow restriction for maintaining inflation. The cooling unit is advantageously used for cooling athletes at competitions, fire fighters and the like.