diff --git a/meteoio/spatialInterpolations/UserAlgorithm.cc b/meteoio/spatialInterpolations/UserAlgorithm.cc
index ab6ea08f1abe7ada353d88bbde0efac03336e87f..8e1e68b19debd35af33a033c7a325bd399e170b6 100644
--- a/meteoio/spatialInterpolations/UserAlgorithm.cc
+++ b/meteoio/spatialInterpolations/UserAlgorithm.cc
@@ -24,20 +24,22 @@ namespace mio {
 
 USERInterpolation::USERInterpolation(const std::vector< std::pair<std::string, std::string> >& vecArgs, const std::string& i_algo, const std::string& i_param, TimeSeriesManager& i_tsm,
                                                                  GridsManager& i_gdm)
-                                : InterpolationAlgorithm(vecArgs, i_algo, i_param, i_tsm), gdm(i_gdm), filename(), grid2d_path(), subdir(), file_ext(), time_constant(false), lowest_priority(false)
+                                : InterpolationAlgorithm(vecArgs, i_algo, i_param, i_tsm), gdm(i_gdm), filename(), grid2d_path(), subdir(), file_ext(), naming("YYYYMMDDhhmmss_PARAM"), time_constant(false), lowest_priority(false)
 {
 	for (size_t ii=0; ii<vecArgs.size(); ii++) {
 		if (vecArgs[ii].first=="SUBDIR") {
 			subdir = vecArgs[ii].second;
 		} else if (vecArgs[ii].first=="EXT") {
 			file_ext = vecArgs[ii].second;
+		} else if (vecArgs[ii].first=="NAMING") {
+			naming = vecArgs[ii].second;
 		} else if (vecArgs[ii].first=="TIME_CONSTANT") {
 			const std::string where( "Interpolations2D::"+i_param+"::"+i_algo );
 			IOUtils::parseArg(vecArgs[ii], where, time_constant);
 		} else if (vecArgs[ii].first=="LOWEST_PRIORITY") {
 			const std::string where( "Interpolations2D::"+i_param+"::"+i_algo );
 			IOUtils::parseArg(vecArgs[ii], where, lowest_priority);
-		} 
+		}
 	}
 
 	if (!subdir.empty()) subdir += "/";
@@ -52,14 +54,61 @@ double USERInterpolation::getQualityRating(const Date& i_date)
 		filename = subdir + param + file_ext;
 	} else {
 		date = i_date;
-		filename = subdir + date.toString(Date::NUM) + "_" + param + file_ext;
+		std::string timenum = date.toString(Date::NUM);
+		std::string timestr = naming;
+		bool invalidnaming = false;
+		size_t pos = 0;
+		// Insert year
+		pos = naming.find("YYYY");
+		if (pos!=std::string::npos)
+			timestr.replace(pos, 4, timenum.substr(0, 4));
+		else
+			invalidnaming = true;
+		// Insert month
+		pos = naming.find("MM");
+		if (pos!=std::string::npos)
+			timestr.replace(pos, 2, timenum.substr(4, 2));
+		else
+			invalidnaming = true;
+		// Insert day
+		pos = naming.find("DD");
+		if (pos!=std::string::npos)
+			timestr.replace(pos, 2, timenum.substr(6, 2));
+		else
+			invalidnaming = true;
+		// Insert hours
+		pos = naming.find("hh");
+		if (pos!=std::string::npos)
+			timestr.replace(pos, 2, timenum.substr(8, 2));
+		else
+			invalidnaming = true;
+		// Insert minutes
+		pos = naming.find("mm");
+		if (pos!=std::string::npos)
+			timestr.replace(pos, 2, timenum.substr(10, 2));
+		else
+			invalidnaming = true;
+		// Insert seconds (optional)
+		pos = naming.find("ss");
+		if (pos!=std::string::npos)
+			timestr.replace(pos, 2, timenum.substr(12, 2));
+		// Insert param
+		pos = naming.find("PARAM");
+		if (pos!=std::string::npos)
+			timestr.replace(pos, 5, param);
+		else
+			invalidnaming = true;
+
+		if (invalidnaming) throw InvalidArgumentException("[E] Invalid NAMING key (" + naming + ") for "+algo+" interpolation algorithm.\n", AT);
+
+		filename = subdir + timestr + file_ext;
 	}
 
 	if (!FileUtils::validFileAndPath(grid2d_path+"/"+filename)) {
 		std::cerr << "[E] Invalid grid filename for "+algo+" interpolation algorithm: " << grid2d_path+"/"+filename << "\n";
 		return 0.0;
 	}
-	
+
 	const bool has_data = FileUtils::fileExists(grid2d_path+"/"+filename);
 
 	if (!lowest_priority)
diff --git a/meteoio/spatialInterpolations/UserAlgorithm.h b/meteoio/spatialInterpolations/UserAlgorithm.h
index d0e3b2910807c333266a6368f821c81007f28acf..5536c73d64f0dcca84d9310c8b92126881653b46 100644
--- a/meteoio/spatialInterpolations/UserAlgorithm.h
+++ b/meteoio/spatialInterpolations/UserAlgorithm.h
@@ -32,12 +32,13 @@ namespace mio {
  * be ".asc". But the following arguments allow overriding it:
  *  - SUBDIR: look for grids in the provided subdirectory of GRID2DPATH;
  *  - EXT: use another file extension.
- * 
- * The files must be named according to the following schema: <b>{numeric date with second resolution}_{capitalized meteo parameter}.{ext}</b>, for example 20081201150000_TA.asc.
- * But the following argument allows overriding this.
+ *  - NAMING: provide file name template using YYYY for year, MM for month, DD for day, hh for hour, mm for minute, ss for second (optional) and PARAM for parameter name.
+ *		Examples:
+ *		- param::user::naming = YYYYMMDDhhmmss_PARAM (default) searches for files named: <b>{numeric date with second resolution}_{capitalized meteo parameter}.{ext}</b>, for example 20081201150000_TA.asc.
+ *		- TA::user::naming = YYYY-MM-DDThh.mm_PARAM searches for files named 2008-12-01T15.00_TA.asc.
  *  - TIME_CONSTANT: if true, use the same grid for all timesteps (default: false). If TIME_CONSTANT is set to true, files must be named according to:
  *    <b>{capitalized meteo parameter}.{ext}</b>, for example TA.asc.
- * 
+ *
  *  If no grid exists for a given timestamp and parameter, the algorithm returns a zero rating so any other interpolation algorithm can pickup
  * and provide a fallback. Therefore, it is not necessary to provide grids for all time steps but one can focuss on only the relevant and interesting
  * time steps. The following argument changes this behavior:
@@ -54,6 +55,7 @@ namespace mio {
  * PSUM::algorithms   = USER	# read grids from GRID2DPATH/precip with the ".dat" extension
  * PSUM::user::subdir = precip
  * PSUM::user::ext    = .dat
+ * PSUM::user::naming = YYYY-MM-DDThh.mm.ss_PARAM
  *
  * TSG::algorithms    = USER     # read grids from GRID2DPATH using the GRID2D plugin
  * TSG::user::ext     = .asc
@@ -70,7 +72,7 @@ class USERInterpolation : public InterpolationAlgorithm {
 		std::string getGridFileName() const;
 		GridsManager& gdm;
 		std::string filename, grid2d_path;
-		std::string subdir, file_ext;
+		std::string subdir, file_ext, naming;
 		bool time_constant, lowest_priority;
 };