Here's a simple and far-from-optimal condition guaranteeing uniform convergence. Suppose for that there exists $C>0$ such that for any positive integer $n$ $\newcommand{\bR}{{\mathbb{R}}}$ $$ \int_\bR |f^{(n)}(x)| e^{-x^2/2} dx\leq C^n. $$ In this case the associated Hermite series is $$ \sum_{n\geq 0} \frac{c_n}{n!} H_n(x), $$ where $$ c_n=\frac{1}{\sqrt{2\pi}}\int_\bR f^{(n)}(x) e^{-x^2/2} dx. $$ and this converges to $f$ uniformly on compacts. This follows [from known asymptotic estimates for Hermite polynomials][1]. For more precise results, you need to look at Gaussian-Sobolev spaces and the Ornstein-Uhlenbeck operator $H$. [1]: https://dlmf.nist.gov/18.15#v