Strike water temperature can be calculated on lots of online sites, just find one that thinks in metric (rationally).
Or you can calculate it your self, remember that the calculation is all on mass but 1kg of water is a litre (ish).
Strike Temp = [((0.4*Grain Mass)+Water Mass)*Target Temp]-(0.4*Grain Mass*Grain Temp) / Water Mass
It actually makes a lot more sense if you derive it from the standard dilution equations but that's another story.
Your grain temperature should be pretty close to ambient, or stick your thermometer in the middle of the grist for a few minutes and use the reading.
Mark