diff --git a/src/basic/time-util.c b/src/basic/time-util.c
index fb54ba276c..e54c829623 100644
--- a/src/basic/time-util.c
+++ b/src/basic/time-util.c
@@ -1022,7 +1022,7 @@ int parse_timestamp(const char *t, usec_t *ret) {
         if (timezone_is_valid(tz, LOG_DEBUG)) {
                 SAVE_TIMEZONE;
 
-                if (setenv("TZ", strjoina(":", tz), /* overwrite = */ true) < 0)
+                if (setenv("TZ", tz, /* overwrite = */ true) < 0)
                         return negative_errno();
 
                 return parse_timestamp_impl(t, max_len, /* utc = */ false, /* isdst = */ -1, /* gmtoff = */ 0, ret);
diff --git a/src/shared/calendarspec.c b/src/shared/calendarspec.c
index 3569f15db4..0e12e55a97 100644
--- a/src/shared/calendarspec.c
+++ b/src/shared/calendarspec.c
@@ -1426,13 +1426,7 @@ static int calendar_spec_next_usec_impl(const CalendarSpec *spec, usec_t usec, u
         return 0;
 }
 
-typedef struct SpecNextResult {
-        usec_t next;
-        int return_value;
-} SpecNextResult;
-
 int calendar_spec_next_usec(const CalendarSpec *spec, usec_t usec, usec_t *ret_next) {
-        SpecNextResult *shared, tmp;
         int r;
 
         assert(spec);
@@ -1440,39 +1434,13 @@ int calendar_spec_next_usec(const CalendarSpec *spec, usec_t usec, usec_t *ret_n
         if (isempty(spec->timezone))
                 return calendar_spec_next_usec_impl(spec, usec, ret_next);
 
-        shared = mmap(NULL, sizeof *shared, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, 0);
-        if (shared == MAP_FAILED)
-                return negative_errno();
+        SAVE_TIMEZONE;
 
-        r = safe_fork("(sd-calendar)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG_SIGKILL|FORK_WAIT, NULL);
-        if (r < 0) {
-                (void) munmap(shared, sizeof *shared);
+        r = RET_NERRNO(setenv("TZ", spec->timezone, /* overwrite = */ true));
+        if (r < 0)
                 return r;
-        }
-        if (r == 0) {
-                char *colon_tz;
 
-                /* tzset(3) says $TZ should be prefixed with ":" if we reference timezone files */
-                colon_tz = strjoina(":", spec->timezone);
+        tzset();
 
-                if (setenv("TZ", colon_tz, 1) != 0) {
-                        shared->return_value = negative_errno();
-                        _exit(EXIT_FAILURE);
-                }
-
-                tzset();
-
-                shared->return_value = calendar_spec_next_usec_impl(spec, usec, &shared->next);
-
-                _exit(EXIT_SUCCESS);
-        }
-
-        tmp = *shared;
-        if (munmap(shared, sizeof *shared) < 0)
-                return negative_errno();
-
-        if (tmp.return_value == 0 && ret_next)
-                *ret_next = tmp.next;
-
-        return tmp.return_value;
+        return calendar_spec_next_usec_impl(spec, usec, ret_next);
 }
diff --git a/src/test/test-calendarspec.c b/src/test/test-calendarspec.c
index 9abbde622f..0b1cbacd62 100644
--- a/src/test/test-calendarspec.c
+++ b/src/test/test-calendarspec.c
@@ -44,12 +44,9 @@ static void _test_one(int line, const char *input, const char *output) {
 static void _test_next(int line, const char *input, const char *new_tz, usec_t after, usec_t expect) {
         _cleanup_(calendar_spec_freep) CalendarSpec *c = NULL;
         usec_t u;
-        char *old_tz;
         int r;
 
-        old_tz = getenv("TZ");
-        if (old_tz)
-                old_tz = strdupa_safe(old_tz);
+        SAVE_TIMEZONE;
 
         if (!isempty(new_tz) && !strchr(new_tz, ','))
                 new_tz = strjoina(":", new_tz);
@@ -68,9 +65,6 @@ static void _test_next(int line, const char *input, const char *new_tz, usec_t a
                 assert_se(r >= 0 && u == expect);
         else
                 assert_se(r == -ENOENT);
-
-        assert_se(set_unset_env("TZ", old_tz, true) == 0);
-        tzset();
 }
 #define test_next(input, new_tz, after, expect) _test_next(__LINE__, input,new_tz,after,expect)
 
diff --git a/src/test/test-time-util.c b/src/test/test-time-util.c
index 7569f89ca0..7bcf0ae7ee 100644
--- a/src/test/test-time-util.c
+++ b/src/test/test-time-util.c
@@ -13,13 +13,7 @@
 #define TRIAL 100u
 
 static void set_timezone(const char *tz) {
-        if (!tz)
-                ASSERT_OK_ERRNO(unsetenv("TZ"));
-        if (isempty(tz))
-                ASSERT_OK_ERRNO(setenv("TZ", tz, /* overwrite = */ true));
-        else
-                ASSERT_OK_ERRNO(setenv("TZ", strjoina(":", tz), /* overwrite = */ true));
-
+        ASSERT_OK(set_unset_env("TZ", tz, /* overwrite = */ true));
         tzset();
         log_info("TZ=%s, tzname[0]=%s, tzname[1]=%s", strna(getenv("TZ")), strempty(tzname[0]), strempty(tzname[1]));
 }
@@ -421,7 +415,7 @@ static void test_format_timestamp_impl(usec_t x) {
          * timezone may provide time shifted 1 hour from the original. See
          * https://github.com/systemd/systemd/issues/28472 and https://github.com/systemd/systemd/pull/35471 */
         bool ignore =
-                streq_ptr(getenv("TZ"), ":Africa/Windhoek") &&
+                streq_ptr(getenv("TZ"), "Africa/Windhoek") &&
                 (x_sec > y_sec ? x_sec - y_sec : y_sec - x_sec) == 3600;
 
         log_full(ignore ? LOG_WARNING : LOG_ERR,
@@ -1113,14 +1107,14 @@ TEST(usec_shift_clock) {
 TEST(in_utc_timezone) {
         SAVE_TIMEZONE;
 
-        assert_se(setenv("TZ", ":UTC", 1) >= 0);
+        assert_se(setenv("TZ", "UTC", 1) >= 0);
         assert_se(in_utc_timezone());
         ASSERT_STREQ(tzname[0], "UTC");
         ASSERT_STREQ(tzname[1], "UTC");
         assert_se(timezone == 0);
         assert_se(daylight == 0);
 
-        assert_se(setenv("TZ", ":Europe/Berlin", 1) >= 0);
+        assert_se(setenv("TZ", "Europe/Berlin", 1) >= 0);
         assert_se(!in_utc_timezone());
         ASSERT_STREQ(tzname[0], "CET");
         ASSERT_STREQ(tzname[1], "CEST");
diff --git a/src/timedate/timedatectl.c b/src/timedate/timedatectl.c
index 0bbc740d46..0e8e705a50 100644
--- a/src/timedate/timedatectl.c
+++ b/src/timedate/timedatectl.c
@@ -58,7 +58,6 @@ typedef struct StatusInfo {
 
 static int print_status_info(const StatusInfo *i) {
         _cleanup_(table_unrefp) Table *table = NULL;
-        const char *old_tz = NULL, *tz, *tz_colon;
         char a[LINE_MAX];
         TableCell *cell;
         struct tm tm;
@@ -79,13 +78,10 @@ static int print_status_info(const StatusInfo *i) {
         (void) table_set_ellipsize_percent(table, cell, 100);
 
         /* Save the old $TZ */
-        tz = getenv("TZ");
-        if (tz)
-                old_tz = strdupa_safe(tz);
+        SAVE_TIMEZONE;
 
         /* Set the new $TZ */
-        tz_colon = strjoina(":", isempty(i->timezone) ? "UTC" : i->timezone);
-        if (setenv("TZ", tz_colon, true) < 0)
+        if (setenv("TZ", isempty(i->timezone) ? "UTC" : i->timezone, /* overwrite = */ true) < 0)
                 log_warning_errno(errno, "Failed to set TZ environment variable, ignoring: %m");
         else
                 tzset();
@@ -158,13 +154,6 @@ static int print_status_info(const StatusInfo *i) {
         if (r < 0)
                 return table_log_add_error(r);
 
-        /* Restore the $TZ */
-        r = set_unset_env("TZ", old_tz, true);
-        if (r < 0)
-                log_warning_errno(r, "Failed to set TZ environment variable, ignoring: %m");
-        else
-                tzset();
-
         r = table_add_many(table,
                            TABLE_FIELD, "System clock synchronized",
                            TABLE_BOOLEAN, i->ntp_synced,