ok, so I reduced the range to 30, and it was playable- for 10 seconds. Then, as the screen began to fill with snowflakes, the frames per second dropped to 2, then to 1, as the program froze and stopped responding. Again, I had to force quit.
If you are going to write a new weather mod, I would suggest not using snowflakes, but use little white dots. Also, reduce visibility using fog. Only show snowflakes close to the player, maybe within 8 blks or so. For rain, do the same.
My experience just now was that there were millions of snowflakes way off into the distance. My computer froze as it was required to compute the ever-increasing barrage of snowflakes all around me. More were appearing, thicker, and thicker as the program locked up