This study provides an in-depth investigation into the temperature sensitivity of Silicon-based Fin Field-Effect Transistor (Si-FinFET), highlighting their viability as nano-dimensional temperature sensors. The Multi-Gate Field-Effect Transistor (MuGFET) simulation framework was utilised to model and analyse the thermal response characteristics of Si-FinFET structures. Simulations of the current voltage (I-V) profiles were conducted across a range of temperatures and gate lengths (Lg = 10, 20, and 30 nm), with the temperature sensitivity quantified under a diode-mode operational scheme. The optimum sensitivity was identified through the maximum differential current (∆I) within the supply voltage window (VDD = 0-1 V). Notably, a linear augmentation in temperature sensitivity was observed as the channel length increased from 10 nm to 20 nm, underscoring the scalability and enhanced thermal responsivity of Si-FinFET architectures for advanced nanoscale sensing applications.