We live in Tokyo and are going to fly our parents in their early 70's over for a 10-12 day visit-their first time in Japan...We are wondering what you experienced travellers think is a better time to visit Tokyo (with side trips within Japan): Feb 14-26 or late March? Weatherwise, I know that it will be slightly warmer by late March but possibly more rain and more tourists?
Thanks for any help/advice!

More tourists, for sure. No snow.

late march is far better, definitely.
cherry blossom season in central tokyo.
typical peak bloom there is last few days of march. the best season to visit chidorigafuchi moat/kitanomaru park, ueno park,etc.

end of march would be a better choice, the cherry blossoms are too beautiful to be missed...

check the 2010 forecast here - http://www.nationalcherryblossomfest...dex.php?id=404

Definitely agree with end of March.

Most definitely end of March to catch hanami.