June is ordinarily considered to be a good month to visit Hanoi for it offers agreeable weather throughout with its warm temperatures combined with clear skies.
Hanoi's summer months are generally sunny and dry, from May to August, with highs around 24-28 °C (75-82 °F). June is particularly a nice month for outdoor activities such as visiting temples, walking through the Old Quarter, or exploring the West Lake, which is one of the largest attractions in Hanoi.
June can be one of the best times to visit Hanoi, provided that the weather is pleasant-that is, cool and not so crowded, in comparison with peak season. However, one must note that during this month, Hanoi also passes from the rainy season to summer, so expect some occasional rain too. If this isn't a concern for you but want some solitude from the other tourists, June does allow for a good mixed offering during one's stay. Just don't forget lightweight wear and an umbrella or raincoat while packing.
June seems to be a mixed blessing for Hanoi-although still depending on what one looks for in the trip-as it is still summer, and summer, in Hanoi, means temperatures could go up to the 30s (Celsius), with high levels of humidity. Moreover, June gets into the rainy season; thus, you should probably expect heavy rains every now and then-sometimes gently, other times more vehemently. Certainly, they are brief showers, making way for lots of sunny periods as well.