I am not sure which is your problem (if you have a 2D matrix, Matlab should be able to plot it), but here's a tentative answer.

If you can obtain a 2D matrix (M) with each column being a different chronological series (say, for a different variable), plotting that should be easy. If you want to plot all variables in the same plot just do:

plot(time, M)

If you just want to plot one variable you can select the column n by:

plot(time, M(:,n))

On the other side, I tried to reproduce your error by downloading some hydrological projections from here. The structure of the data is not the same you describe, but is similar. For example, for runoff:

total_runoff

       Size: 57x32x73x1

       Dimensions: longitude,latitude,time,projection

Applying a line similar to yours,

variable = ncread(fname,'total_runoff', [1 1 1 1], [57, 32, inf, 1], [1 1 1 1]);

I obtain a variable of dimensions (57x32x73). Say I want to select the data for one grid point (1, 1):

tr_pt = variable(1, 1, :)

The ':' is used to select all values in the given dimension. Then tr_pt has dimensions (1x1x73). Matlab is not able to plot it, and it returns the error message "Error using plot. Data may not have more than 2 dimensions". To solve this error it possible to use squeeze to remove singleton dimensions:

tr_pt=squeeze(variable(1, 1, :)

so that now tr_pt has dimensions (73x1) and can be plotted.

http://gdo-dcp.ucllnl.org/downscaled_cmip_projections/dcpInterface.html#Welcome

Jordi Prats thank you so much! The tr_tp=squeeze(variable(1,1,:) function is the first time I've actually been able to produce a plot I can make sense of. Sorry for miscommunicating the error too, this is one of the first times I've really used this program for a large amount of data and I'm still learning the ropes. Is there any way I can produce a plot of the entire coordinate grid though instead of an individual plot of each longitude and latitude. My hope was to get statistics like average monthly precipitation and surface evaporation for my entire research area. I'm working with an area that's 80 longitude units by 48 latitude units in Matlab over a 100 year period divided monthly into 1200 units over 1 projection path so 80x48x1200x1. Do you think there is someway I could redo the conditional function to condense the hydrology variable from 4-D to 2-D in a way that would let me plot the whole grid?

Well, you could reshape your 4D matrix to a 2D one:

M = reshape(variable, 80*48, 1200);

so that you obtain a 3840x1200 matrix. If you prefer the time as the first dimension, you can transpose the matrix:

M_tr = M';

That should work.