Protecting HVAC during extreme weather

Living in an area that constantly faces heavy rains and occasional storms, my concern is whether my HVAC unit is really prepared for such conditions. Last year, after a particularly strong storm, my system began making strange noises and didn’t cool efficiently anymore. That experience left me worried, and now I want to be proactive before the next storm season hits. Has anyone found reliable ways to storm-proof their HVAC system, especially without breaking the bank?