Inspired by this reddit post, I made a printable version.

To print in two colors, when slicing in Cura, go to Extensions → Post Processing → Modify G-Code → Add a script → Pause at height. Start by printing with white filament and then, during the pause, load up black filament.

As an alternative method to getting the second color, you could print the whole thing in black and then pour thinned acrylic paint into the lower area. I haven't personally tried this method but I've seen people talking about it online.

To render the OpenSCAD file, you'll need to have the ClearviewHwy 3-B font installed. Available here. In the Customizer, there are also options for Liberation Sans (installed with OpenSCAD) and Public Sans Black.

The temperature guide is certainly not 100% accurate. I determined that the original sign got its numbers from this paper which used measurements from AZ. Atmospheric and weather conditions will probably result in different correlations.