diff --git a/core/libs/prx/libc/src/Time.cpp b/core/libs/prx/libc/src/Time.cpp
index 1da075245..1a49ca85d 100644
--- a/core/libs/prx/libc/src/Time.cpp
+++ b/core/libs/prx/libc/src/Time.cpp
@@ -17,6 +17,9 @@
 
 namespace {
 
+constexpr const char* WEEKDAY_NAMES[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
+constexpr const char* MONTH_NAMES[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
+constexpr std::size_t ASCTIME_SIZE = sizeof("Sun Jan-2147483648 -2147483648:-2147483648:-2147483648 -2147483648\n");
 constexpr std::int64_t SECONDS_PER_DAY = 86400;
 constexpr std::int64_t DAYS_FROM_MARCH_TO_YEAR_END = 306;
 
@@ -324,8 +327,12 @@ size_t APS5_VABI libc_strftime_nid_postfix(char* str, size_t count, const char*
 }
 
 char* APS5_VABI asctime_nid_postfix(const GuestTm* timeptr) {
-    const std::tm host = toHostTm(*timeptr);
-    return std::asctime(&host);
+    static thread_local char result[ASCTIME_SIZE];
+    const char* weekday = timeptr->tm_wday >= 0 && timeptr->tm_wday < 7 ? WEEKDAY_NAMES[timeptr->tm_wday] : "???";
+    const char* month = timeptr->tm_mon >= 0 && timeptr->tm_mon < 12 ? MONTH_NAMES[timeptr->tm_mon] : "???";
+    std::snprintf(result, sizeof(result), "%s %s%3d %.2d:%.2d:%.2d %lld\n", weekday, month, timeptr->tm_mday,
+        timeptr->tm_hour, timeptr->tm_min, timeptr->tm_sec, 1900LL + timeptr->tm_year);
+    return result;
 }
 
 char* APS5_VABI ctime_nid_postfix(const int64_t* timer) {
diff --git a/core/libs/tests/GuestTimeConversion.cpp b/core/libs/tests/GuestTimeConversion.cpp
index 3edc8418d..821b509de 100644
--- a/core/libs/tests/GuestTimeConversion.cpp
+++ b/core/libs/tests/GuestTimeConversion.cpp
@@ -19,6 +19,7 @@ GuestTm* APS5_VABI libc_localtime_nid_postfix(const std::int64_t*);
 GuestTm* APS5_VABI localtime_nid_postfix(const std::int64_t*);
 GuestTm* APS5_VABI gmtime_s_nid_postfix(const std::int64_t*, GuestTm*);
 GuestTm* APS5_VABI localtime_s_nid_postfix(const std::int64_t*, GuestTm*);
+char* APS5_VABI asctime_nid_postfix(const GuestTm*);
 std::int64_t APS5_VABI mktime_nid_postfix(GuestTm*);
 std::size_t APS5_VABI strftime_nid_postfix(char*, std::size_t, const char*, const GuestTm*);
 void APS5_VABI tzset_nid_postfix(void);
@@ -68,6 +69,17 @@ static void CheckConcurrent(Converter convert, BufferedConverter buffered, const
     Require(convert(&invalid) == nullptr, "Unrepresentable time was accepted");
 }
 
+static GuestTm UtcTime(std::int64_t timer) {
+    GuestTm utc{};
+    Require(gmtime_s_nid_postfix(&timer, &utc) == &utc, "UTC conversion failed");
+    return utc;
+}
+
+static void CheckAsctime(const GuestTm& brokenDown, const char* expected) {
+    const char* text = asctime_nid_postfix(&brokenDown);
+    Require(text != nullptr && std::strcmp(text, expected) == 0, "asctime did not format the broken-down time");
+}
+
 struct UtcCase {
     std::int64_t timer;
     int year;
@@ -249,6 +261,14 @@ int main() {
     GuestTm scratch{};
     Require(gmtime_s_nid_postfix(&underflow, &scratch) == nullptr, "Unrepresentable negative time was accepted");
 
+    CheckAsctime(UtcTime(0), "Thu Jan  1 00:00:00 1970\n");
+    CheckAsctime(UtcTime(-2208988801), "Sun Dec 31 23:59:59 1899\n");
+    CheckAsctime(UtcTime(-30610224000), "Wed Jan  1 00:00:00 1000\n");
+    GuestTm pastMonthEnd = UtcTime(983404800);
+    pastMonthEnd.tm_mon = 1;
+    pastMonthEnd.tm_mday = 29;
+    CheckAsctime(pastMonthEnd, "Thu Feb 29 00:00:00 2001\n");
+
     const std::int64_t epoch = 0;
     GuestTm local{};
     std::memset(&local, 0xAA, sizeof(local));