Yeah with weather-causing abilities the faster Pokemon's ability always kicks in first, so the slowest Pokemon will always get it's weather.
I always wonder this when I play: If pokemon are so powerful and aggressive, why do they just let humans capture them like that? I feel like they'd put up more of a fight. Especially freaky Pokemon like Rampardos; if that was real you wouldn't even have the time to send out a Pokemon before you're sent into the air by it's deadly headbutt.