Hello Oscar,
It's great to see that you've found your way over to the Community. :) Walking the whole way from Belfast to Derry-Londonderry sounds like an amazing adventure, and I would love to help you find the information you're looking for.
During the second half of March you can expect temperatures between 4°C and 15°C degrees, a bit of rain here and there, followed by sunny spells. For more information about the irish weather, take a look
here.
On the Walk NI page you can find an overview of all the available walking routes from
Belfast along the
Causeway Coast and Glens to
County Londonderry. Not all of these routes connect via an off-road path, so sometimes you'll have to divert to the road. These usually will have a safe area for pedestrians, but it is always a good idea to wear clothes or gear that make you visible to drivers.
Have you planned out the exact route you'd like to walk yet? Are there any parts where you need some help to find the right path or route?
Walk NI also has a super handy online map available with plenty of destinations and details.
Wild camping on the island of Ireland is only allowed in a few places, like for instance in the Wicklow Mountains, and only with permission of the forest ranger. This is why it isn't recommended to set up your tent in fields along the way, as you might be on someone's private property.
Have you thought about staying in hostels, guesthouses or B&B's along the way? You can find all tourist board approved accommodation
here. Simply type in the name of the place where you would like to stay, and all of the available options will pop up.
I hope you'll receive more tips from our other members, and please don't hesitate to give me a shout if there is anything else you need. :)
Happy planning!
Melin