A method for determining the temperature of a metal strip, the strip being movable inside a cooling apparatus of a hot rolling installation, the method being implemented by an electronic determination device and comprising: - acquiring a measure of a temperature (T k) of a strip portion at a current time instant (k); - estimating, at the current time instant (k), a heat flux (φ k) extracted from the strip portion inside the cooling apparatus according to a thermal model, the thermal model being configured for modeling: + an air cooling corresponding to the cooling of the strip portion by air radiation and air convection, + a coolant header cooling corresponding to the cooling of the strip portion by at least one coolant header, and + a remaining coolant cooling corresponding to the cooling of the strip portion by coolant remaining on the strip portion after the strip portion passed under the at least one coolant header; - computing a temperature (T k+1) of the strip portion at a next time instant (k+1) from the acquired measure of the temperature (T k) and the estimated extracted heat flux (φ k); characterised in that, for the coolant header cooling, the thermal model is further configured for modeling both: + an impingement cooling corresponding to the cooling of the strip portion by coolant impinging from the at least one coolant header, and + a parallel flow cooling corresponding to the cooling of the strip portion by coolant falling at a given distance from the at least one coolant header. - acquiring a measure of a temperature (T k) of a strip portion at a current time instant (k); - estimating, at the current time instant (k), a heat flux (φ k) extracted from the strip portion inside the cooling apparatus according to a thermal model, the thermal model being configured for modeling: + an air cooling corresponding to the cooling of the strip portion by air radiation and air convection, + a coolant header cooling corresponding to the cooling of the strip portion by at least one coolant header, and + a remaining coolant cooling corresponding to the cooling of the strip portion by coolant remaining on the strip portion after the strip portion passed under the at least one coolant header; + an air cooling corresponding to the cooling of the strip portion by air radiation and air convection, + a coolant header cooling corresponding to the cooling of the strip portion by at least one coolant header, and + a remaining coolant cooling corresponding to the cooling of the strip portion by coolant remaining on the strip portion after the strip portion passed under the at least one coolant header; - computing a temperature (T k+1) of the strip portion at a next time instant (k+1) from the acquired measure of the temperature (T k) and the estimated extracted heat flux (φ k); characterised in that, for the coolant header cooling, the thermal model is further configured for modeling both: + an impingement cooling corresponding to the cooling of the strip portion by coolant impinging from the at least one coolant header, and + a parallel flow cooling corresponding to the cooling of the strip portion by coolant falling at a given distance from the at least one coolant header. + an impingement cooling corresponding to the cooling of the strip portion by coolant impinging from the at least one coolant header, and + a parallel flow cooling corresponding to the cooling of the strip portion by coolant falling at a given distance from the at least one coolant header.