diff --git a/src/basic/time-util.h b/src/basic/time-util.h
index 087f5324ef..79a6715656 100644
--- a/src/basic/time-util.h
+++ b/src/basic/time-util.h
@@ -205,13 +205,17 @@ static inline usec_t usec_sub_signed(usec_t timestamp, int64_t delta) {
         return usec_sub_unsigned(timestamp, (usec_t) delta);
 }
 
+/* The last second we can format is 31. Dec 9999, 1s before midnight, because otherwise we'd enter 5 digit
+ * year territory. However, since we want to stay away from this in all timezones we take one day off. */
+#define USEC_TIMESTAMP_FORMATTABLE_MAX_64BIT ((usec_t) 253402214399000000) /* Thu 9999-12-30 23:59:59 UTC */
+/* With a 32bit time_t we can't go beyond 2038...
+ * We parse timestamp with RFC-822/ISO 8601 (e.g. +06, or -03:00) as UTC, hence the upper bound must be off
+ * by USEC_PER_DAY. See parse_timestamp() for more details. */
+#define USEC_TIMESTAMP_FORMATTABLE_MAX_32BIT (((usec_t) INT32_MAX) * USEC_PER_SEC - USEC_PER_DAY)
 #if SIZEOF_TIME_T == 8
-  /* The last second we can format is 31. Dec 9999, 1s before midnight, because otherwise we'd enter 5 digit
-   * year territory. However, since we want to stay away from this in all timezones we take one day off. */
-#  define USEC_TIMESTAMP_FORMATTABLE_MAX ((usec_t) 253402214399000000)
+#  define USEC_TIMESTAMP_FORMATTABLE_MAX USEC_TIMESTAMP_FORMATTABLE_MAX_64BIT
 #elif SIZEOF_TIME_T == 4
-/* With a 32bit time_t we can't go beyond 2038... */
-#  define USEC_TIMESTAMP_FORMATTABLE_MAX ((usec_t) 2147483647000000)
+#  define USEC_TIMESTAMP_FORMATTABLE_MAX USEC_TIMESTAMP_FORMATTABLE_MAX_32BIT
 #else
 #  error "Yuck, time_t is neither 4 nor 8 bytes wide?"
 #endif
diff --git a/src/test/test-date.c b/src/test/test-date.c
index 097066b61a..16c6d4e5be 100644
--- a/src/test/test-date.c
+++ b/src/test/test-date.c
@@ -101,8 +101,8 @@ int main(int argc, char *argv[]) {
         test_should_fail("9999-12-31 00:00:00 UTC");
         test_should_fail("10000-01-01 00:00:00 UTC");
 #elif SIZEOF_TIME_T == 4
-        test_should_pass("2038-01-19 03:14:07 UTC");
-        test_should_fail("2038-01-19 03:14:08 UTC");
+        test_should_pass("2038-01-18 03:14:07 UTC");
+        test_should_fail("2038-01-18 03:14:08 UTC");
 #endif
 
         return 0;
diff --git a/src/test/test-time-util.c b/src/test/test-time-util.c
index e974520bbe..44eb0d25f6 100644
--- a/src/test/test-time-util.c
+++ b/src/test/test-time-util.c
@@ -617,8 +617,8 @@ TEST(format_timestamp_range) {
         test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX + 1, TIMESTAMP_US_UTC, "--- XXXX-XX-XX XX:XX:XX.XXXXXX UTC");
         test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX + 1, TIMESTAMP_DATE, "--- XXXX-XX-XX");
 #elif SIZEOF_TIME_T == 4
-        test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX, TIMESTAMP_UTC, "Tue 2038-01-19 03:14:07 UTC");
-        test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX, TIMESTAMP_DATE, "Tue 2038-01-19");
+        test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX, TIMESTAMP_UTC, "Mon 2038-01-18 03:14:07 UTC");
+        test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX, TIMESTAMP_DATE, "Mon 2038-01-18");
         test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX + 1, TIMESTAMP_UTC, "--- XXXX-XX-XX XX:XX:XX UTC");
         test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX + 1, TIMESTAMP_US_UTC, "--- XXXX-XX-XX XX:XX:XX.XXXXXX UTC");
         test_format_timestamp_one(USEC_TIMESTAMP_FORMATTABLE_MAX + 1, TIMESTAMP_DATE, "--- XXXX-XX-XX");