Several factors at play. Are you near a major city? Are you carrying your own malpractice? Capable of doing hearts? Taking overnight call?
I practice in New England. I’ve seen/heard of anywhere from $150-$300/hr for hourly locums work. If you have your own malpractice insurance, can do the credentialing yourself, don’t need meals/lodging/etc you should be able to get more hourly.