Well, i run WH control. Just love the decks aestethics. As for Spell ST matchup - well, its a tedious matchup, and not a favourable one. Basicly, frightener is a must. It gives at least some value to your control tools. Other than that - delay, delay, delay. Remember that even if you dont have crones - the threat of them forces him to keep going (im not sure if you can win this matchup without them). Other than that - quen WH riders are usually what allow me to stay in game. Playing them shielded with gold units on skellige storm row is usually how i stay in game. Obviously scorch/Epidemic effects are a huge threat, operator and eredin allow to replace the losses. That trio going in round 2 is really neccecery, or i can never amass enough power.
Your list doesnt really have long-term high value cards like riders i use, neither do you run crones. Im not sure if the matchup is even possible for you.
Best tech choice against spell ST is Vamp Regis, but with your list i dont think hes gonna cut it. If i were running dagon fog, i would probably try Ancient foglets as a growing threat. Obviously sheer value that harpies bring into other matchups makes them awesome, but against weather control its just multiple bodies to be decimated.
Overall, with your list i dont see you winning this matchup. You can attempt to tech in Vamp Regis + Crones, but it will be a fairly different deck.
You can either abandon matchup all together if deck performs in others. Or you can try to tech in "tempo cheats". Ancient foglets, WH riders, stuff that grows. Or, or even better, alongside plain powerhouse in crones. You need to threaten spell ST constantly that you can take a round in 1 card. They are limited to 3 DBPs, and you need to force them onto the board.
Sad conclusion is, your deck in its current state is "food" for Spell"tael.