diff --git a/src/tz.cpp b/src/tz.cpp
index a34f795..143e902 100644
--- a/src/tz.cpp
+++ b/src/tz.cpp
@@ -2831,7 +2831,7 @@ remote_version()
 {
     std::string version;
     std::string str;
-    if (download_to_string("http://www.iana.org/time-zones", str))
+    if (download_to_string("https://www.iana.org/time-zones", str))
     {
         CONSTDATA char db[] = "/time-zones/releases/tzdata";
         CONSTDATA auto db_size = sizeof(db) - 1;
@@ -3238,7 +3238,7 @@ remote_download(const std::string& version)
     }
 #  endif  // _WIN32
 
-    auto url = "http://www.iana.org/time-zones/releases/tzdata" + version +
+    auto url = "https://data.iana.org/time-zones/releases/tzdata" + version +
                ".tar.gz";
     bool result = download_to_file(url, get_download_gz_file(version),
                                    download_file_options::binary);