I am scheduling a month in Vietnam. I can do either October 2018 or March/April 2019. Initial readings led me to believe the spring would be best as the fall is rainy. I have read recently that October is good. Please advise. Thanks!

The best time for travelling in Vietnam is March/ April (South to North of VN). If you do not mind rain in Oct/ Nov, it is still ok.

Being a long thin mountainous country, a lot depends on what you want to do and where you want to go. Weather patterns in Asia seem to becoming more erratic in recent years so nothing is certain but I would go in MARCH which is one of the very few months when you can be reasonably certain of good weather in most parts of the country. The south will get much hotter into April

October is on the cusp of the "season" and generally brings uncertain weather to much of the country. The rainy season is at its peak and you can expect some severe storms, especially in central Vietnam where flooding is quite common. It can be pleasant in Hanoi and Saigon and there likely will be fewer tourists, the major sites will be less crowded and accomodation prices lower.

100% agree with Crellston!

There's something not right because as I know, there're much rain in spring and it's so wet while the fall is quite mild. Anyway, the weather in Vietnam is different from region to region. And October is good time to travel to the North Vietnam.