In this paper, the behaviour of A2-70 stainless steel is investigated by performing tensile tests on round specimens at different temperatures under quasi-static and dynamic conditions. The relationship between thermal softening and strain is firstly investigated, highlighting that the variability of the necking strain under different temperatures is a proof of such interaction. The competing effects of strain rate and temperature in respectively delaying and anticipating the necking onset are also quantified analytically, referring to multiplicative hardening models with and without the coupling of strain and temperature. Then, the comparison of necking strains from static and dynamic (Hopkinson bar) tests at different temperatures is analysed, for understanding which effect among thermal softening and dynamic stress amplification prevails in anticipating/delaying the necking. Fracture strains and the shapes of specimens at failure are finally related to the respective strain rates and temperatures.