diff --git a/pysurfex/configuration.py b/pysurfex/configuration.py
index 5f4e86c..3bf238f 100644
--- a/pysurfex/configuration.py
+++ b/pysurfex/configuration.py
@@ -550,7 +550,7 @@ def __init__(self, env, conf):
             gsize = float(env["LGSIZE"])
         trunc = 2  # linear
         if "TRUNC" in env:
-            trunc = int(float(env["TRUNC"]))
+            trunc = float(env["TRUNC"])
         domain_dict = {
             "nam_pgd_grid": {"cgrid": "CONF PROJ"},
             "nam_conf_proj": {