whose to blame??

If the car has its headlights on and the person is jaywalking, the walker is to blame.
If the car has its headlights off and the person is jaywalking, both are to blame.
If the car has its headlights off and the person is on a crosswalk, the driver is to blame.

Under certain circumstances, and they are rare, an incident can be considered an "act of god".

The rain neither can prevent and who knows why the person is in the middle of the road. Perhaps he was helping someone else laying in the middle of the road.

I would say as long as the driver is going slower than the speed limit, because of the rain, has their headlights on, is taking precautions and cooperates with police I don't see any reason to blame the driver.

Both are equally at fault...more so the driver, coz if he can’t see in that pouring rain, in spite of his headlights, then he shouldn’t drive.

Pedestrian.