"I have a medical cannabis card from California, and will be visiting NY. Can I use this to get into dispensaries while on my trip? "
No, you can only use your medical cannabis card in the state that it is issued in. You can only use your California medical cannabis card in California.
julienp
Unlike other states (Nevada and Michigan are good examples), New York dispensaries are not permitted to honor medical cannabis cards from other states.
jeremyu