It must be very difficult to write the opening episode of a brand new murder mystery. You have to introduce the characters and how they interact, and also have a storyline strong enough that people will want to come back next week.
With that in mind, maybe it's too early to dismiss Otenki Onee-san but it wasn't a very good start. A young genius weather forecaster gets a job on a morning TV show presenting the weather. And she also solves crimes. I guess she has a lot of spare time on her hands.
She meets, by chance, a rookie cop and a pathologist and helps them to solve a murder. The crime was simple, but I was interested by the explanation which involved air temperature. If they can keep up this level of ingenuity for each episode, this could be worth watching. Especially if you like the weather. If not, this may bore you senseless.
But enough about the crimes, what about the characters? She is a genius who has difficulty getting on with people and the rookie cop is naive and not taken seriously by his co-workers. So far, things are all very predictable. It's a relief, then, that the pathologist adds a little humour, as he finds himself falling for a woman twenty years younger than himself, and he's not happy about it.
Another series that needs a couple of episodes to get going.