I have an animation to render, and i want snow to fall. i've achieved that with particles, that are objects spawned from a plane high above, so it isn't visible when playing the animation. The problem is, i use a drag force field to prevent the snow particles from falling too fast and looking like rain, but they take a while to reach the ground. Can i do something so the first already at ground level when the animation begins?
I've had the same problem both with the fluttering nature of snowflakes, gravity and needing to have the snowfall showing well into the original animation. The easiest way to achieve the time lag before you get a decent amount of snow is, in addition to what has already been suggested, to simply advance the animation to start the render from frame 250. That gave mine plenty of time for snowflakes to fall and give good cover.
The fluttering effect was achieved by the settings you'll find in my Blender file at this previous question. (I've forgotten how I did it or I'd mention it again)
You can bring your emitter(s) down quite low and render them invisible to the render. I think I did that in the Material tab for the emitter itself - Transparency setting, plus you might also need to tick the Transparency box under the emitter's properties. (cube icon) You'll see how I did that also in the Blender file.
NB: Rendered using OpenGL.
This worked well for me, hope it does for you...