Temperature is a critical determinant of host–pathogen interactions in the respiratory tract, and influenza A virus (IAV) has adapted to the cooler environment of the upper respiratory tract (URT) to enable efficient replication and transmission. The cold-inducible RNA-binding protein (RBP) RBM3 is highly expressed in the URT and stabilises host mRNAs under hypothermic conditions; however, its role in viral infection is not well defined. We identified RBM3 as a key proviral host factor that facilitates IAV replication at sub-physiological temperatures, showing a direct interaction between RBM3 & IAV NP mRNA, via UV crosslinking and immunoprecipitation (iCLIP2) and smiFISH RNA-proximity ligation assay. Mechanistically, we identified that these interactions result in an enhanced half-life of the viral transcript and show for the first time that NP mRNA but not HA mRNA is re-localised to G3BP1 positive stress granules (SGs), possessing a liquid-like property. This effect was abolished in an RNA-binding-deficient RBM3 mutant, confirming the requirement for direct RBM3-NP mRNA interaction. Crucially, this positive regulation of NP mRNA was validated in well differentiated primary nasal epithelial cells, highlighting the physiological relevance of RBM3 in the human URT. These results reveal a temperature sensitive virus-host interaction that promotes IAV replication in the cooler URT, a key site for viral shedding and transmission. By linking temperatures of the URT, host RBP mediated viral mRNA stabilisation and re-localisation to SGs, we uncover a novel mechanism of respiratory virus adaptation and identifies RBM3 as a potential therapeutic target for limiting early-stage viral replication and transmission.