This is my go-to potato salad for BBQs - the red potatoes hold their shape way better than russets and the lemon keeps everything bright instead of heavy. I always make extra because it's even better the next day.
Cover potato chunks with water by 1 inch in a large pot and bring to a boil over medium-high heat.
Add salt to the water and reduce heat to medium once boiling.
Simmer for 9-10 minutes until potatoes are tender but hold their shape when pierced with a fork.
Drain potatoes and let cool completely before proceeding.
Whisk together sour cream, mayonnaise, lemon juice, Dijon mustard, green onions, parsley, and dill in a large bowl.
Season dressing with 1 tsp salt and 1/2 tsp pepper, adjusting to taste.
Add cooled potatoes, celery, and dill pickles to the dressing.
Toss gently to coat without breaking up the potatoes.
Taste and adjust seasoning with more salt, pepper, or lemon juice as needed.
Refrigerate for at least 1 hour before serving.
Notes
Potatoes must be completely cool before mixing or the dressing will become watery. Salad keeps for up to 3 days in the fridge. Thin with milk or water if it thickens while stored.