OK, Ran's weather forecast says rain, how do Yukarin lose against it with umbrella? More over, can't she just gap the rain water above her?

Difference between an umbrella (for keeping out the rain) and a parasol (for keeping out the sunlight). Good question about the rain-gapping, though.

Umbrellas keep out sunlight quite well. Parasols just do it with class while an umbrella out in the sunlight just seems weird. People give me strange looks until they realize that portable shade is amazing.