diff --git a/conf/confbase.Y b/conf/confbase.Y
index 3e88b832..0eafdb14 100644
--- a/conf/confbase.Y
+++ b/conf/confbase.Y
@@ -100,7 +100,8 @@ CF_DECLS
   struct f_prefix px;
   struct proto_spec ps;
   struct channel_limit cl;
-  struct timeformat *tf;
+  struct timeformat tf;
+  struct timeformat *tfp;
   struct settle_config settle;
   struct adata *ad;
   const struct adata *bs;
diff --git a/doc/bird.sgml b/doc/bird.sgml
index b4e333b7..f3c2c026 100644
--- a/doc/bird.sgml
+++ b/doc/bird.sgml
@@ -1489,6 +1489,13 @@ This argument can be omitted if there exists only a single instance.
 	pipe protocol, both directions are always reloaded together (<cf/in/ or
 	<cf/out/ options are ignored in that case).
 
+	<tag><label id="cli-timeformat">timeformat "<m/format1/" [<m/limit/ "<m/format2/"]</tag>
+	Override format of date/time used by BIRD in this CLI session.
+
+	Meaning of "<m/format1/", <m/limit/, and "<m/format2/" is the same as in the
+	<ref id="opt-timeformat" name="timeformat"> configuration option. Also, the
+	same <cf/iso .../ shorthands may be used.
+
 	<tag><label id="cli-down">down</tag>
 	Shut BIRD down.
 
diff --git a/doc/reply_codes b/doc/reply_codes
index e387fed8..69e3a263 100644
--- a/doc/reply_codes
+++ b/doc/reply_codes
@@ -77,3 +77,4 @@ Reply codes of BIRD command-line interface
 9000	Command too long
 9001	Parse error
 9002	Invalid symbol type
+9003	Argument too long
diff --git a/nest/cli.c b/nest/cli.c
index dd0ce407..37f310b0 100644
--- a/nest/cli.c
+++ b/nest/cli.c
@@ -304,6 +304,36 @@ cli_kick(cli *c)
 static list cli_log_hooks;
 static int cli_log_inited;
 
+/* Set time format override for the current session */
+void
+cli_set_timeformat(cli *c, const struct timeformat tf)
+{
+  size_t len1 = strlen(tf.fmt1) + 1;
+  size_t len2 = tf.fmt2 ? strlen(tf.fmt2) + 1 : 0;
+
+  if (len1 > TM_DATETIME_BUFFER_SIZE || len2 > TM_DATETIME_BUFFER_SIZE)
+  {
+    cli_msg(9003, "Format string too long");
+    return;
+  }
+
+  struct timeformat *old_tf = c->tf;
+  struct timeformat *new_tf = mb_allocz(c->pool, sizeof(struct timeformat));
+  new_tf->fmt1 = memcpy(mb_alloc(c->pool, len1), tf.fmt1, len1);
+  new_tf->fmt2 = tf.fmt2 ? memcpy(mb_alloc(c->pool, len2), tf.fmt2, len2) : NULL;
+  new_tf->limit = tf.limit;
+  c->tf = new_tf;
+
+  if (old_tf)
+  {
+    mb_free((void *) old_tf->fmt1);
+    mb_free((void *) old_tf->fmt2);
+    mb_free(old_tf);
+  }
+
+  cli_msg(0, "");
+}
+
 /* Hack for scheduled undo notification */
 extern cli *cmd_reconfig_stored_cli;
 
diff --git a/nest/cli.h b/nest/cli.h
index c3dfc3eb..e9b59c51 100644
--- a/nest/cli.h
+++ b/nest/cli.h
@@ -12,6 +12,7 @@
 #include "lib/resource.h"
 #include "lib/lists.h"
 #include "lib/event.h"
+#include "lib/timer.h"
 #include "lib/tlists.h"
 #include "conf/conf.h"
 
@@ -41,6 +42,7 @@ typedef struct cli {
   struct config *main_config;		/* Main config currently in use */
   int last_reply;
   int restricted;			/* CLI is restricted to read-only commands */
+  struct timeformat *tf;		/* Time format override */
   struct linpool *parser_pool;		/* Pool used during parsing */
   uint log_mask;			/* Mask of allowed message levels */
   uint log_threshold;			/* When free < log_threshold, store only important messages */
@@ -73,6 +75,7 @@ extern struct cli *this_cli;		/* Used during parsing */
 
 void cli_printf(cli *, int, char *, ...);
 #define cli_msg(x...) cli_printf(this_cli, x)
+void cli_set_timeformat(cli *c, const struct timeformat tf);
 
 static inline void cli_separator(cli *c)
 { if (c->last_reply) cli_printf(c, -c->last_reply, ""); };
diff --git a/nest/cmds.c b/nest/cmds.c
index b55d2c23..a596773c 100644
--- a/nest/cmds.c
+++ b/nest/cmds.c
@@ -22,11 +22,10 @@ extern int configuring;
 void
 cmd_show_status(void)
 {
-  byte tim[TM_DATETIME_BUFFER_SIZE];
-
   rcu_read_lock();
   struct global_runtime *gr = atomic_load_explicit(&global_runtime, memory_order_acquire);
-  struct timeformat *tf = &gr->tf_base;
+  struct timeformat *tf = this_cli->tf ?: &gr->tf_base;
+  byte tim[TM_DATETIME_BUFFER_SIZE];
 
   cli_msg(-1000, "BIRD " BIRD_VERSION);
   tm_format_time(tim, tf, current_time());
diff --git a/nest/config.Y b/nest/config.Y
index 4eedca52..c0b468e4 100644
--- a/nest/config.Y
+++ b/nest/config.Y
@@ -191,6 +191,8 @@ CF_ENUM(T_ENUM_MPLS_POLICY, MPLS_POLICY_, NONE, STATIC, PREFIX, AGGREGATE, VRF)
 %type <ps> proto_patt proto_patt2
 %type <cc> channel_start proto_channel
 %type <cl> limit_spec
+%type <tf> timeformat_spec
+%type <tfp> timeformat_which
 %type <net> r_args_for_val
 %type <net_ptr> r_args_for
 %type <t> channel_sym
@@ -453,6 +455,10 @@ debug_default:
 
 conf: timeformat_base ;
 
+timeformat_base:
+   TIMEFORMAT timeformat_which timeformat_spec ';' { *$2 = $3; }
+ ;
+
 timeformat_which:
    ROUTE { $$ = &new_config->tf_route; }
  | PROTOCOL { $$ = &new_config->tf_proto; }
@@ -461,18 +467,14 @@ timeformat_which:
  ;
 
 timeformat_spec:
-   timeformat_which TEXT { *$1 = (struct timeformat){$2, NULL, 0}; }
- | timeformat_which TEXT expr TEXT { *$1 = (struct timeformat){$2, $4, (s64) $3 S_}; }
- | timeformat_which ISO SHORT    { *$1 = TM_ISO_SHORT_S; }
- | timeformat_which ISO SHORT MS { *$1 = TM_ISO_SHORT_MS; }
- | timeformat_which ISO SHORT US { *$1 = TM_ISO_SHORT_US; }
- | timeformat_which ISO LONG    { *$1 = TM_ISO_LONG_S; }
- | timeformat_which ISO LONG MS { *$1 = TM_ISO_LONG_MS; }
- | timeformat_which ISO LONG US { *$1 = TM_ISO_LONG_US; }
- ;
-
-timeformat_base:
-   TIMEFORMAT timeformat_spec ';'
+   TEXT { $$ = (struct timeformat){$1, NULL, 0}; }
+ | TEXT expr TEXT { $$ = (struct timeformat){$1, $3, (s64) $2 S_}; }
+ | ISO SHORT	{ $$ = TM_ISO_SHORT_S; }
+ | ISO SHORT MS	{ $$ = TM_ISO_SHORT_MS; }
+ | ISO SHORT US	{ $$ = TM_ISO_SHORT_US; }
+ | ISO LONG	{ $$ = TM_ISO_LONG_S; }
+ | ISO LONG MS	{ $$ = TM_ISO_LONG_MS; }
+ | ISO LONG US	{ $$ = TM_ISO_LONG_US; }
  ;
 
 /* Interface patterns */
@@ -1004,6 +1006,16 @@ CF_CLI(MRTDUMP, proto_patt mrtdump_mask, (<protocol> | \"<pattern>\" | all) (all
 CF_CLI(RESTRICT,,,[[Restrict current CLI session to safe commands]])
 { this_cli->restricted = 1; cli_msg(16, "Access restricted"); } ;
 
+CF_CLI_HELP(TIMEFORMAT, ..., [[Set time format for this CLI session]])
+CF_CLI(TIMEFORMAT, timeformat_spec, \"<format1>\" [limit \"format2\"] | iso (short | long) [ ms | us ], [[Set time format for this CLI session]])
+{ cli_set_timeformat(this_cli, $2); } ;
+
+CF_CLI_OPT(TIMEFORMAT ISO)
+CF_CLI_OPT(TIMEFORMAT SHORT)
+CF_CLI_OPT(TIMEFORMAT LONG)
+CF_CLI_OPT(TIMEFORMAT MS)
+CF_CLI_OPT(TIMEFORMAT US)
+
 proto_patt:
    CF_SYM_KNOWN { cf_assert_symbol($1, SYM_PROTO); $$.ptr = $1; $$.patt = 0; }
  | ALL  { $$.ptr = NULL; $$.patt = 1; }
diff --git a/nest/proto.c b/nest/proto.c
index 42d479d0..ea521ceb 100644
--- a/nest/proto.c
+++ b/nest/proto.c
@@ -2610,7 +2610,7 @@ proto_cmd_show(struct proto *p, uintptr_t verbose, int cnt)
     p->proto->get_status(p, buf);
 
   rcu_read_lock();
-  tm_format_time(tbuf, &atomic_load_explicit(&global_runtime, memory_order_acquire)->tf_proto, p->last_state_change);
+  tm_format_time(tbuf, this_cli->tf ?: &atomic_load_explicit(&global_runtime, memory_order_acquire)->tf_proto, p->last_state_change);
   rcu_read_unlock();
   cli_msg(-1002, "%-10s %-10s %-10s %-6s %-12s  %s",
 	  p->name,
diff --git a/nest/rt-show.c b/nest/rt-show.c
index 84d6dcb0..e4149e66 100644
--- a/nest/rt-show.c
+++ b/nest/rt-show.c
@@ -50,7 +50,7 @@ rt_show_rte(struct cli *c, byte *ia, rte *e, struct rt_show_data *d, int primary
   int dest = nhad ? (NEXTHOP_IS_REACHABLE(nhad) ? RTD_UNICAST : nhad->dest) : RTD_NONE;
   int flowspec_valid = net_is_flow(e->net) ? rt_get_flowspec_valid(e) : FLOWSPEC_UNKNOWN;
 
-  tm_format_time(tm, &d->tf_route, e->lastmod);
+  tm_format_time(tm, c->tf ?: &d->tf_route, e->lastmod);
   ip_addr a_from = ea_get_ip(a, &ea_gen_from, IPA_NONE);
   if (ipa_nonzero(a_from) && (!nhad || !ipa_equal(a_from, nhad->nh.gw)))
     bsprintf(from, " from %I", a_from);
diff --git a/proto/bfd/bfd.c b/proto/bfd/bfd.c
index 2cb72c54..c85a1b63 100644
--- a/proto/bfd/bfd.c
+++ b/proto/bfd/bfd.c
@@ -1248,7 +1248,7 @@ bfd_show_session(struct bfd_session *s, int details)
 
   rcu_read_lock();
   struct global_runtime *gr = atomic_load_explicit(&global_runtime, memory_order_relaxed);
-  tm_format_time(tbuf, &gr->tf_proto, s->last_state_change);
+  tm_format_time(tbuf, this_cli->tf ?: &gr->tf_proto, s->last_state_change);
   rcu_read_unlock();
 
   if (!details)
diff --git a/sysdep/unix/config.Y b/sysdep/unix/config.Y
index 25eb36ed..42d78c6f 100644
--- a/sysdep/unix/config.Y
+++ b/sysdep/unix/config.Y
@@ -25,7 +25,6 @@ CF_KEYWORDS(GRACEFUL, RESTART, FIXED)
 
 %type <i> log_mask log_mask_list log_cat cfg_timeout debug_unix latency_debug_mask latency_debug_flag latency_debug_list
 %type <t> cfg_name
-%type <tf> timeformat_which
 %type <t> syslog_name
 
 CF_GRAMMAR