Lightning can strike far from the parent thunderstorm, with common distances up to 10 to 25 miles away. However, in rare cases, lightning—specifically "anvil lightning" or "bolts from the blue"—can strike as far as 100 miles or more away from the cloud that produced it. The longest recorded lightning strike was cloud-to-cloud over 477 miles, but such extreme distances for cloud-to-ground strikes are less common. Positive lightning strikes tend to travel farther (up to about 25 miles) than negative strikes (up to about 10 miles). Most lightning strikes occur close to or within the thunderstorm itself, but anvil lightning can travel many tens of miles downwind from the storm's upper cloud anvil. This phenomenon is responsible for lightning strikes that seem to come "from the blue" sky with no immediate thunderstorm nearby. In terms of safety, the rule is that if thunder can be heard, lightning is close enough to be a danger, typically within 10 to 12 miles. So in summary:

• Typical maximum distance for lightning strike from a thunderstorm: about 10 to 25 miles.
• Rare anvil lightning can strike 100 miles or more away.
• Longest lightning strike on record: 477 miles (cloud-to-cloud).
• Hearing thunder means lightning is close enough to be dangerous.

This range depends on thunderstorm strength, wind patterns, and storm structure.