diff --git a/src/aggregate.jl b/src/aggregate.jl
new file mode 100644
index 0000000..36a6d35
--- /dev/null
+++ b/src/aggregate.jl
@@ -0,0 +1,302 @@
+# function Base.sum(xout, xin)    
+    
+#     xout .=  Base.sum(xin)
+   
+# end
+
+# function Base.sum(cube::YAXArray, kwargs...)    
+
+#     indims = InDims("time")    
+#     outdims = OutDims()
+    
+#     mapCube(sum, cube, indims=indims, outdims=outdims)
+# end
+
+"""
+    daily_max_mean_min(xout, xin)
+
+Compute the daily maximum, mean, and minimum values from the input array `xin` and store the results in the output array `xout`.
+
+# Arguments
+- `xout::AbstractArray`: The output array where the computed values will be stored.
+- `xin::AbstractArray`: The input array from which the values will be computed.
+
+# Details
+- The function replaces missing values in `xin` with `NaN` before computing the maximum, mean, and minimum values.
+- The computed values are stored in `xout` as an array, where each row corresponds to a different index in `index_list`.
+
+"""
+function daily_max_mean_min(xout, xin; index_list)
+    xout .= NaN
+    if !all(ismissing, xin)
+        for i in eachindex(index_list)
+            data = view(xin, index_list[i])
+            if !all(ismissing, data)
+                xout[i,1] = maximum(skipmissing(data))
+                xout[i,2] = mean(skipmissing(data))
+                xout[i,3] = minimum(skipmissing(data))
+            end
+        end        
+    end    
+end
+
+"""
+        daily_max_mean_min(data::YAXArray)
+
+Compute the daily maximum, mean, and minimum values from a YAXArray Cube.
+
+# Arguments
+- `data::YAXArray`: A Cube of data
+
+# Returns
+- A Cube with daily maximum, mean and minimum values. The output cube has the following dimensions:
+    - `time`: Time dimension
+    - `stats`: max, mean and min   
+
+
+"""
+function daily_max_mean_min(cube::YAXArray, kwargs...)    
+
+    time_to_index = cube.time
+    time_index = yearmonthday.(time_to_index)
+    new_dates = unique(time_index)
+    index_in_cube = [findall(==(i), time_index) for i in unique(time_index)]   
+    
+    # Dimensions
+    indims = InDims("Ti")    
+    # outdims = OutDims(RangeAxis("time", dates_builder_yearmonthday(new_dates)), CategoricalAxis("stats",["max","mean","min"]))
+    outdims = OutDims(Dim{:Ti}(dates_builder_yearmonthday(new_dates)), CategoricalAxis("stats",["max","mean","min"]))
+    
+    mapCube(daily_max_mean_min, cube, indims=indims, outdims=outdims, index_list=index_in_cube)
+end
+
+
+"""
+    percentiles(cube::YAXArray, quantiles=[0.1, 0.5, 0.9])
+
+Compute the percentiles of a YAXArray cube along the "number" dimension (represent member for a given seasonal prediction simulation) and return a new cube with the computed percentiles along the "time", "longitude", and "latitude" dimensions.
+
+# Arguments
+- `cube::YAXArray`: The input YAXArray cube.
+- `quantiles::Vector{Float64}`: The quantiles to compute. Default is `[0.1, 0.5, 0.9]`.
+
+# Returns
+A new YAXArray cube with the computed percentiles along the "time", "longitude", and "latitude" dimensions.
+
+"""
+function percentiles(cube::YAXArray, quantiles=[0.1, 0.5, 0.9];lonname="longitude", latname="latitude")    
+    
+    indims = InDims("number")    
+    outdims = OutDims("Ti", lonname, latname)
+    
+    mapCube(percentiles, cube, indims=indims, outdims=outdims, quantiles=quantiles)
+end
+
+"""
+    diff(xout, xin)
+
+Compute the difference between consecutive elements of `xin` and store the result in `xout`. A 0.0 is added at the beginning of the output array.
+
+# Arguments
+- `xout`: An array to store the difference values.
+- `xin`: An array of values.
+
+"""
+function diff(xout, xin)   
+        
+    xout .=  vcat(0.0, Base.diff(xin[:]))    
+   
+end
+
+"""
+    diff(cube::YAXArray, kwargs...)
+
+Compute the difference between consecutive time steps in the given `cube`.
+
+# Arguments
+- `cube::YAXArray`: The input data cube.
+- `kwargs...`: Additional keyword arguments.
+
+# Returns
+- A new `YAXArray` object containing the difference between consecutive time steps.
+
+"""
+function diff(cube::YAXArray)    
+
+
+    indims = InDims("Ti")    
+    outdims = OutDims("Ti")
+    
+    mapCube(diff, cube, indims=indims, outdims=outdims)
+end
+
+"""
+    cumsum(xout, xin)
+
+Compute the cumulative sum of the elements in `xin` and store the result in `xout`.
+
+# Arguments
+- `xout`: An array to store the cumulative sum.
+- `xin`: An array containing the elements to be summed.
+
+"""
+function cumsum(xout, xin)    
+    
+    xout .=  cumsum(xin)
+   
+end
+
+"""
+    cumsum(cube::YAXArray, kwargs...)
+
+Compute the cumulative sum along the "time" dimension of the input `cube`.
+
+# Arguments
+- `cube`: The input YAXArray cube.
+- `kwargs`: Additional keyword arguments.
+
+# Returns
+A new YAXArray cube with the cumulative sum computed along the "time" dimension.
+
+"""
+function cumsum(cube::YAXArray, kwargs...)    
+
+    indims = InDims("Ti")    
+    outdims = OutDims("Ti")
+    
+    mapCube(cumsum, cube, indims=indims, outdims=outdims)
+end
+
+
+
+"""
+    daily_fct(xout, xin; fct::Function, index_list = time_to_index)
+
+Apply a function `fct` to aggregate data from `xin` into `xout` on a daily basis **used internally**
+
+# Arguments
+- `xout`: Output array to store the aggregated data.
+- `xin`: Input array containing the data to be aggregated.
+- `fct`: Function to be applied for aggregation.
+- `index_list`: (optional) Function to convert time to index.
+
+"""
+function daily_fct(xout, xin; fct::Function, index_list = time_to_index)
+    
+    xout .= NaN
+    if !all(ismissing, xin)
+        for i in eachindex(index_list)
+            data = view(xin, index_list[i])
+            if !all(ismissing, data)
+                xout[i] = fct(skipmissing(data))
+            end
+        end
+        
+    end
+    
+end 
+
+"""
+    daily_fct(cube::YAXArray; fct::Function=mean, shifthour=0, kwargs...)
+
+Apply a function `fct` to process the data in `cube` on a daily basis. Assumes that the Cube have sub-daily values.
+
+# Arguments
+- `cube::YAXArray`: The input data cube.
+- `fct::Function`: The function to apply for processus sub-daily values. Default is `mean`.
+- `shifthour::Int`: The number of hours to shift the time values. Default is 0.
+- `kwargs...`: Additional keyword arguments to be passed to the aggregation function.
+
+# Returns
+A new `YAXArray` with aggregated data on a daily basis.
+
+"""
+function daily_fct(cube::YAXArray; fct::Function=mean, shifthour=0, kwargs...)
+    time_to_index = cube.Ti .+ Dates.Hour(shifthour)
+    time_index = yearmonthday.(time_to_index)
+    new_dates = unique(time_index)
+    index_in_cube = [findall(==(i), time_index) for i in unique(time_index)]   
+    
+    # Dimensions
+    indims = InDims("Ti")        
+    outdims = OutDims(Dim{:Ti}(dates_builder_yearmonthday(new_dates)))
+    
+    mapCube(daily_fct, cube, indims=indims, outdims=outdims, fct=fct, index_list=index_in_cube)
+end
+
+
+function yearly_clim(xout, xin; fct::Function=mean, index_list = time_to_index)
+    
+    xout .= NaN
+    if !all(ismissing, xin)
+        for i in eachindex(index_list)
+            data = view(xin, index_list[i])
+            if !all(ismissing, data)
+                xout[i] = fct(skipmissing(data))
+            end
+        end
+        
+    end
+    
+end 
+"""
+    yearly_clim(cube::YAXArray; fct::Function=mean, kwargs...)
+
+Compute the yearly climatology of a YAXArray.
+
+# Arguments
+- `cube::YAXArray`: The input YAXArray containing the data.
+- `fct::Function`: The function to be applied to each yearly subset of the data. Default is `mean`.
+- `kwargs...`: Additional keyword arguments to be passed to the function. **not yet implemented**
+
+# Returns
+A new YAXArray containing the yearly climatology.
+"""
+
+function yearly_clim(cube::YAXArray; fct::Function=mean, kwargs...)
+    time_to_index = cube.Ti;
+    time_index = year.(time_to_index);
+    new_dates = unique(time_index);
+    index_in_cube = [findall(==(i), time_index) for i in unique(time_index)]
+
+    # Dimensions
+    indims = InDims("Ti")        
+    outdims = OutDims(Dim{:Ti}(dates_builder_yearmonthday_hardcode(new_dates, imois=7, iday=1)))
+
+    mapCube(yearly_clim, cube, fct=fct, indims=indims, outdims=outdims, index_list=index_in_cube)
+end
+
+"""
+    function daily_max(xout, xin; index_list = time_to_index)
+
+xout = expected output
+xin = input that I get from the Cube
+index_list = 
+"""
+function daily_max(xout, xin; index_list = time_to_index)
+    
+    xout .= NaN
+    if !all(ismissing, xin)
+        for i in eachindex(index_list)
+            data = view(xin, index_list[i])
+            if !all(ismissing, data)
+                xout[i] = maximum(skipmissing(data))
+            end
+        end
+        
+    end
+    
+end 
+
+function daily_max(cube::YAXArray, kwargs...)
+    time_to_index = cube.time;
+    time_index = yearmonthday.(time_to_index);
+    new_dates = unique(time_index);
+    index_in_cube = [findall(==(i), time_index) for i in unique(time_index)]   
+    
+    # Dimensions
+    indims = InDims("Ti")        
+    outdims = OutDims(Dim{:Ti}(dates_builder_yearmonthday(new_dates)))
+    
+    mapCube(daily_max, cube, indims=indims, outdims=outdims, index_list=index_in_cube)
+end