diff --git a/NEWS.md b/NEWS.md
index 2a9cffb623360ea12ba8874d7bef2853324db8f6..f108f5db59e4223372e2c4917de88e00ab23618d 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -5,6 +5,7 @@
     + EnsClustering vignette
     + EnsClustering has a new parameter 'time_dim'
     + CST_BiasCorrection has na.rm paramter
+    + CST_Anomaly allows to smooth the climatology with filter.span parameter
 - Fixes
     + CST_Anomaly handles exp, obs or both
     + PlotForecastPDF vignette displays figures correctly
diff --git a/R/CST_Anomaly.R b/R/CST_Anomaly.R
index c6de2ad1a697f9a54adba5254563835d2fe9de70..6e33c3411d1000abb0c15e4994aa9d7fbd473b23 100644
--- a/R/CST_Anomaly.R
+++ b/R/CST_Anomaly.R
@@ -12,7 +12,7 @@
 #'@param cross A logical value indicating whether cross-validation should be applied or not. Default = FALSE.
 #'@param memb A logical value indicating whether Clim() computes one climatology for each experimental data 
 #'product member(TRUE) or it computes one sole climatology for all members (FALSE). Default = TRUE.
-#'
+#'@param filter_span a numeric value indicating the degree of smoothing. This option is only available if parameter \code{cross} is set to FALSE.  
 #'@param dim_anom An integer indicating the dimension along which the climatology will be computed. It 
 #'usually corresponds to 3 (sdates) or 4 (ftime). Default = 3.
 #'
@@ -52,7 +52,8 @@
 #'
 #'
 #'@export
-CST_Anomaly <- function(exp = NULL, obs = NULL, cross = FALSE, memb = TRUE, dim_anom = 3) {
+CST_Anomaly <- function(exp = NULL, obs = NULL, cross = FALSE, memb = TRUE,
+                        filter_span = NULL, dim_anom = 3) {
  
   if (!inherits(exp, 's2dv_cube') & !is.null(exp) || 
       !inherits(obs, 's2dv_cube') & !is.null(obs)) {
@@ -144,7 +145,22 @@ CST_Anomaly <- function(exp = NULL, obs = NULL, cross = FALSE, memb = TRUE, dim_
     #  Without cross-validation 
   } else {
     tmp <- Clim(var_exp = exp$data, var_obs = obs$data, memb = memb)
-    
+    if (!is.null(filter_span)) {
+        if (is.numeric(filter_span)) {
+            pos_dims <- names(dim(tmp$clim_exp))
+            reorder <- match(pos_dims, c('ftime',
+                             pos_dims[-which(pos_dims == 'ftime')]))
+            tmp$clim_obs <- aperm(apply(tmp$clim_obs, c(1 : 
+               length(dim(tmp$clim_obs)))[-which(names(dim(tmp$clim_obs)) == 'ftime')],
+               .Loess, loess_span = filter_span), reorder)
+            tmp$clim_exp <- aperm(apply(tmp$clim_exp, c(1 :
+               length(dim(tmp$clim_exp)))[-which(names(dim(tmp$clim_exp)) == 'ftime')],
+               .Loess, loess_span = filter_span), reorder)
+        } else {
+            warning("Paramater 'filter_span' is not numeric and any filter",
+                    " is being applied.")
+        }
+    }
     if (memb) { 
       clim_exp <- tmp$clim_exp
       clim_obs <- tmp$clim_obs
@@ -193,3 +209,10 @@ CST_Anomaly <- function(exp = NULL, obs = NULL, cross = FALSE, memb = TRUE, dim_
     return(list(exp = exp, obs = obs)) 
   }
 }
+.Loess <- function(clim, loess_span) {
+  data <- data.frame(ensmean = clim, day = 1 : length(clim))
+  loess_filt <- loess(ensmean ~ day, data, span = loess_span)
+  output <- predict(loess_filt)
+  return(output)
+}
+
diff --git a/man/CST_Anomaly.Rd b/man/CST_Anomaly.Rd
index 365cbf4615fe69382625ac7b25a94975024cd498..1157416852e78b063b6c4db1606e2d3e2b8401cf 100644
--- a/man/CST_Anomaly.Rd
+++ b/man/CST_Anomaly.Rd
@@ -4,7 +4,14 @@
 \alias{CST_Anomaly}
 \title{Anomalies relative to a climatology along selected dimension with or without cross-validation}
 \usage{
-CST_Anomaly(exp = NULL, obs = NULL, cross = FALSE, memb = TRUE, dim_anom = 3)
+CST_Anomaly(
+  exp = NULL,
+  obs = NULL,
+  cross = FALSE,
+  memb = TRUE,
+  filter_span = NULL,
+  dim_anom = 3
+)
 }
 \arguments{
 \item{exp}{an object of class \code{s2dv_cube} as returned by \code{CST_Load} function, containing the seasonal forecast experiment data in the element named \code{$data}.}
@@ -16,6 +23,8 @@ CST_Anomaly(exp = NULL, obs = NULL, cross = FALSE, memb = TRUE, dim_anom = 3)
 \item{memb}{A logical value indicating whether Clim() computes one climatology for each experimental data 
 product member(TRUE) or it computes one sole climatology for all members (FALSE). Default = TRUE.}
 
+\item{filter_span}{a numeric value indicating the degree of smoothing. This option is only available if parameter \code{cross} is set to FALSE.}
+
 \item{dim_anom}{An integer indicating the dimension along which the climatology will be computed. It 
 usually corresponds to 3 (sdates) or 4 (ftime). Default = 3.}
 }