There are a couple of similes in chapter 8 during the fire at Miss Maudie's. When looking at the fire, Scout says to Jem,
"Jem, it looks like a pumpkin."
Here the house in flames is being compared to a big orange pumpkin. Then in narration she says right after that,
"Smoke was rolling off our house and Miss Rachel's house like fog off a riverbank..."
This comparison is between smoke and fog. One other comparison is the snowman that they made in that same chapter. Scout says,
"He looks like Stephanie Crawford with her hands on her hips. Fat in the middle and little-bitty arms."