If there is thunder, there physically MUST be lightning. However, thunder and lightning do not require rain. This could either be a thunderstorm that is not directly over you (maybe up to 45 miles away) or what’s called a dry thunderstorm, where it will thunder, and there will be lightning, but the rain produced by the storm will evaporate well before it hits the ground. Dry thunderstorms are common in the western United States in the summer. Hope I helped!
Thunder is the sonic boom caused by the rapid heating and expansion of air left by lightning. Thunder does not need rain in order to happen. If you do not see the lightning, there are several reasons why. First, the lightning could be CC(cloud to cloud) and you just don’t see it. The last reason is that the storm may be too far for you to see the lightning.