Is the additional damage from weakness doubled on a critical hit?

Question

In Pathfinder 2e, some creatures have weakness. When they take damage matching their weakness, they take additional damage. Is this damage from weakness doubled on a critical hit?

For example, the Ice Linnorm has weakness 10 for fire. Imagine a player attacks it with fire damage and scores a critical hit. Their normal damage is 1d10. How much damage did they deal? Is it 2d10+10, or 2d10+20?

I'm aware that the Core Rulebook describes how to calculate damage done. However, found it difficult to walk through those steps and understand the interaction between weakness and critical hits.

Answer 1

It is not doubled

On page 450 of the Core Rulebook we find the four steps of determining damage:

• 1. Roll dice + account for modifiers
• 2. Determine type
• 3. Apply resistance or weakness
• 4. Reduce HP

Doubling the damage (for any reason) is listed on the next page as the last type of modifier in step 1. Thus it happens before any weaknesses are applied in step 3.