Forecasting Velocity

(Based mostly on a Mike Cohn technique, though simplified somewhat. See Ch. 16 of _Agile Estimating and Planning_)

One possible way: Hopefully you have 8-10 iterations to calculate an average. 3 is probably the minimum. If you have less than 4 iterations of data, just use the average. If you have never run an iteration, then run one, and use that velocity as the average.
One possible way: Hopefully you have 8-10 iterations to draw from. Take the average of the lowest 3 velocities. If you have less than 4 iterations of data, then multiple the average velocity by some number between about .6-.8.
One possible way: Hopefully you have 8-10 iterations to draw from. Take the average of the highest 3 velocities. If you have less than 4 iterations of data, then multiple the average velocity by some number between about 1.2-1.6.