In terms of precipitation, rainfall in Hanoi ranges from 0.6 - 11.7 inches per month. August is typically the wettest month, when rainfall can reach 11.7 in. December is typically the driest time to visit Hanoi when rainfall is around 0.6 in.
If weather is an important factor for your trip to Hanoi, use this chart to help with planning. For those seeking warmer temperatures, June is the ideal time of year to visit, when temperatures reach an average of 84.2 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 62.6 F).