Scrying or reading the future is not an exact science. The
future is not static in the way the past is. Each decision we make,
alters the path we are on.
The reading is only a view into one possible future. If
everything remains the same, the outcome is highly likely. So, a
reading of something about to happen (in the very near future) has
a better chance of being accurate, than a reading of something that
may take place in a year or two.
Add to that, the reading itself can alter the probability of the
outcome, in that, if you know something is going to happen, you may
do something, purposefully or inadvertently that will alter the
outcome.