A good option would be to use granules, such as Demand G Granules. They can be applied around the perimeter of your home outdoors to control ants. This product does need to be watered in for it to be activated so during the rainy season, this would be ideal until it dries up and you can use the Termidor SC.
Depending on how heavy the rain was will depend on if you will need to reapply. If the rain was only light and you had just completed a Termidor treatment in a trench for termite prevention then you should be fine. If it was a heavy rain for a long period of time then you may need to reapply. If you were using the Termidor to spray around the perimeter of your home for ants and general insects, then you will likely need to reapply it on a day when no rain is expected for at least 24 hours.
Unfortunately, this is not a common situation and therefore, we are unable to advice. We recommend contacting the emergency number on the safety data sheet (SDS), 1-800-424-9300 and we also recommend to contact the company that performed the treatment.
Best Regards,