<p>Ceramic materials are widely used in thermal systems due to their high thermal stability, corrosion resistance and dependable performance in humid environments, where dehumidification-induced condensation significantly influences thermal performance and efficiency. Motivated by this, the present study introduces a novel transient investigation of heat and mass transfer in a semi-spherical porous ceramic fin under condensation condition. Semi-spherical porous fin made of Si₃N₄ and SiC are analysed to assess the combined influence of geometry, material properties and moisture condensation on thermal performance. The nonlinear governing equations, incorporating Darcy’s law and moisture diffusion are transformed into dimensionless form and solved using the Finite Difference Method, with validation against existing literature. The results indicate that the semi-spherical porous fin exhibits enhanced heat dissipation compared to the rectangular fin with temperature variations reaching 73.68% for Si₃N₄ and 60.04% for SiC. Furthermore, SiC consistently demonstrates superior thermal performance by maintaining a higher temperature distribution of 18.26% compared to Si₃N₄. An increase in relative humidity leads to a reduction in temperature distribution by up to 7.31% for Si₃N₄ and 0.5% for SiC, accompanied by a decline in fin efficiency due to intensified condensation and latent heat loss. The effects of other governing parameters on temperature distribution and efficiency are quantitatively examined, highlighting the importance of transient and moisture-related effects in porous ceramic fin performance. These results offer practical insight for designing reliable thermal management components in HVAC, electronic cooling and energy systems operating in moisture-rich environments.</p>