Is it right practice to validate temperature data with reanalysis data?
No. One should not attempt to validate raw in situ measurements with reanalysis data. Reanalysis data contain partial information from observations, but are mostly model fields and are provided at very coarse resolution (~1$^\circ$ longitude). In situ measurements are subject to very local, small scale effects, and have different meaning from reanalysis. One is always free to compare the two datasets, but this would not be validation in any meaningful way.