Of course, by the Julian reckoning Pascha stays within the spring. But what the OP is wondering about is what happens when Julian "spring" ends up in Gregorian summer, or fall, or winter. I.e. if we are celebrating Pascha while outside the leaves are falling and the days are lengthening, perhaps there is something wrong.
For my part, as a traditionalist, I argue that, if the celebration of Pascha really depends on spring weather, than by that logic, Orthodox in the southern hemisphere should invert the calendar. But then you lose the unity of worship which was the whole point of the original Paschal controversy.