When to visit Bhutan

October is a festive season, so you can expect a lot of tourist in the country. However since May and October are both considered peak travelling season, you will pay the same amount of daily tariff. If you dont plan your trip in advance, confirming reservations is not going to be easy in either months.
In terms of weather, I think May is just perfect right before the summer heat and October is warm right before the cold winter.
Personally I think these are the two best months to visit Bhutan.

Sorry i missed out on your other question. It is correct that all your meals are paid for. It is included in the daily tariff. While some of your meals would already be fixed at certain tourist restaurant, for some your guide may suggest a couple of options you can pick from.
However there would definitely be a cap on how much you can spend on each meal for example deciding to eat at a 5 star hotel restaurant, your operator may charge you a premium on that. OH and your daily tariff does not include alcoholic beverages.

Hey Sharon,

We visited Bhutan in late October early November period. Bhutan was beautiful. The valleys were beautifully spread with paddy fields. Local farmers were harvesting their produce and it was an amazing experience to watch them lead a simple life.

The weather could not be any better. We generally had warm sunny day with clear blue sky which was perfect for our sightseeing activities. You should definitely consider going there in fall season.