It depends bro. Even the picture you used are from Kuala Lumpur. That being said, our local grab driver DID deliver during rainy days. The only time they avoid is they having trouble with the traffic. Also, I think the majority of Malaysian (spoken on behalf of others without their consent 🤣) has the understanding of delay might occurred and food might be served cold during rainy days ordering food delivery was quite unwise.

As your experience last night, that's probably the best case scenario already. Just like that one time my wife was out, I'm stuck home with the kids and there's nothing left for us to cook/eat for dinner, so we got the Panda send us half soaked fried rice, and we're grateful for that and even tip the rider extra for his effort.