But nowhere on the page does anyone say "it worked!" or "it was a boondoggle!", let alone share a statistical analysis that says "rain changed by X sigma over normal". That's a bit disappointing.
According to:
https://www.globalsecurity.org/military/ops/popeye.htm
"In the end, however, it proved impossible to determine the amount of additional rainfall caused by cloud-seeding rather than other factors, and thus justify the recurring outlay. The Defense Intelligence Agency estimated that seeding increased rainfall "in limited areas up to 30 percent above that predicted for the existing conditions," but this figure admittedly was the result of "empirical and theoretical techniques based on units expended and the physical properties of the air mass seeded"-in short, a scientific guess. Sensor data showed only that the enemy consistently experienced difficulty keeping traffic moving through the monsoon rains, a normal problem for that time of year."
(1) It is not possible to precisely quantify the effects due to lack of sufficient ground stations to report
(2) Defence Intelligence Agency estimates a 30% above the predictions for existing existing conditions in specified areas
[0] https://web.archive.org/web/20090612231729/http://www.sunshi...
Does it work? The Army definitely believed it could work at the time, but even today, nobody is sure. Many countries use cloud seeding in a routine basis for civil purposes, but there's still no scientific consensus [0] on the effectiveness of Cloud Seeding. Some researchers believes it works, others don't.
[0] https://en.wikipedia.org/wiki/Cloud_seeding#Effectiveness