diff --git a/apps/desktop/src/components/grid/TemporalCellEditor.vue b/apps/desktop/src/components/grid/TemporalCellEditor.vue
index 63a759f1f..cd037d384 100644
--- a/apps/desktop/src/components/grid/TemporalCellEditor.vue
+++ b/apps/desktop/src/components/grid/TemporalCellEditor.vue
@@ -1,10 +1,10 @@
 <script setup lang="ts">
-import { computed, nextTick, onMounted, ref } from "vue";
+import { computed, nextTick, onMounted, ref, watch } from "vue";
 import type { FocusOutsideEvent, PointerDownOutsideEvent } from "reka-ui";
 import { CalendarClock, ChevronDown, ChevronUp, CircleSlash } from "@lucide/vue";
 import { Button } from "@/components/ui/button";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
-import { formatTemporalInputValue, type TemporalCellEditorKind } from "@/lib/dataGridTemporalEditor";
+import { formatTemporalInputValue, stepTemporalInputValue, type TemporalCellEditorKind } from "@/lib/dataGridTemporalEditor";
 
 const props = withDefaults(
   defineProps<{
@@ -29,19 +29,20 @@ const emit = defineEmits<{
 
 const open = ref(true);
 const triggerRef = ref<HTMLButtonElement | null>(null);
+const localValue = ref(props.modelValue);
 let closeHandled = false;
 let isCommitting = false;
 
 const hasDate = computed(() => props.kind !== "time");
 const hasTime = computed(() => props.kind !== "date");
-const displayValue = computed(() => props.modelValue || "NULL");
+const displayValue = computed(() => localValue.value || "NULL");
 const triggerClass = computed(() =>
   props.variant === "inline"
     ? "cell-edit-input flex h-9 w-full items-center gap-2 rounded border bg-background px-2 text-left text-xs outline-none hover:border-primary/60 focus:border-primary"
     : ["cell-edit-input absolute inset-0 z-10 flex items-center gap-1 border-2 border-primary bg-background py-0 text-left text-xs outline-none", props.cellLayout === "transpose" ? "px-1.5" : "px-2.5"],
 );
 const dateParts = computed(() => {
-  const text = formatTemporalInputValue(props.modelValue, "date");
+  const text = formatTemporalInputValue(localValue.value, "date");
   const match = /^(\d{4})-(\d{2})-(\d{2})$/.exec(text);
   if (!match) {
     const now = new Date();
@@ -51,8 +52,8 @@ const dateParts = computed(() => {
 });
 
 const timeValue = computed(() => {
-  if (props.kind === "time") return formatTemporalInputValue(props.modelValue, "time") || "00:00:00";
-  return formatTemporalInputValue(props.modelValue, "datetime").split("T")[1] || "00:00:00";
+  if (props.kind === "time") return formatTemporalInputValue(localValue.value, "time") || "00:00:00";
+  return formatTemporalInputValue(localValue.value, "datetime").split("T")[1] || "00:00:00";
 });
 
 const timeParts = computed(() => {
@@ -64,12 +65,20 @@ onMounted(() => {
   nextTick(() => triggerRef.value?.focus());
 });
 
+watch(
+  () => props.modelValue,
+  (value) => {
+    localValue.value = value;
+  },
+);
+
 function setOpen(value: boolean) {
   open.value = value;
   if (!value && props.commitOnClose && !closeHandled) finishCommit();
 }
 
 function setModelValue(value: string) {
+  localValue.value = value;
   emit("update:modelValue", value);
 }
 
@@ -90,7 +99,7 @@ function updateDateFromInput(part: "day" | "month" | "year", event: Event) {
 }
 
 function stepDate(part: "day" | "month" | "year", delta: number) {
-  updateDate(part, dateParts.value[part] + delta);
+  setModelValue(stepTemporalInputValue(localValue.value, props.kind, part, delta));
 }
 
 function updateTime(part: "hour" | "minute" | "second", rawValue: string | number) {
@@ -108,9 +117,7 @@ function updateTimeFromInput(part: "hour" | "minute" | "second", event: Event) {
 }
 
 function stepTime(part: "hour" | "minute" | "second", delta: number) {
-  const max = part === "hour" ? 23 : 59;
-  const current = Number(timeParts.value[part]) || 0;
-  updateTime(part, (current + delta + max + 1) % (max + 1));
+  setModelValue(stepTemporalInputValue(localValue.value, props.kind, part, delta));
 }
 
 function flushInputValue(target: EventTarget | null) {
diff --git a/apps/desktop/src/lib/dataGridTemporalEditor.ts b/apps/desktop/src/lib/dataGridTemporalEditor.ts
index 4428e5c1b..e44d2d8e2 100644
--- a/apps/desktop/src/lib/dataGridTemporalEditor.ts
+++ b/apps/desktop/src/lib/dataGridTemporalEditor.ts
@@ -43,6 +43,29 @@ export function parseTemporalInputValue(value: string, kind: TemporalCellEditorK
   return date && normalizedTime ? `${date} ${normalizedTime}` : text.replace("T", " ");
 }
 
+export type TemporalCellEditorPart = "year" | "month" | "day" | "hour" | "minute" | "second";
+
+export function stepTemporalInputValue(value: string, kind: TemporalCellEditorKind, part: TemporalCellEditorPart, delta: number): string {
+  const dateParts = temporalDateParts(value);
+  const timeParts = temporalTimeParts(value, kind);
+
+  if (part === "year") dateParts.year = Math.max(1, Math.min(9999, dateParts.year + delta));
+  else if (part === "month") dateParts.month = Math.max(1, Math.min(12, dateParts.month + delta));
+  else if (part === "day") dateParts.day = Math.max(1, Math.min(31, dateParts.day + delta));
+  else {
+    const max = part === "hour" ? 23 : 59;
+    timeParts[part] = (timeParts[part] + delta + max + 1) % (max + 1);
+  }
+
+  dateParts.day = Math.max(1, Math.min(daysInMonth(dateParts.year, dateParts.month), dateParts.day));
+  const dateText = [String(dateParts.year).padStart(4, "0"), String(dateParts.month).padStart(2, "0"), String(dateParts.day).padStart(2, "0")].join("-");
+  const timeText = [timeParts.hour, timeParts.minute, timeParts.second].map((item) => String(item).padStart(2, "0")).join(":");
+
+  if (kind === "date") return dateText;
+  if (kind === "time") return timeText;
+  return `${dateText} ${timeText}`;
+}
+
 function normalizeTemporalType(dataType: string | undefined): string {
   return (dataType ?? "").toLowerCase().replace(/_/g, "").replace(/[(),]/g, " ").replace(/\s+/g, " ").trim();
 }
@@ -52,3 +75,23 @@ function normalizeTimeInput(text: string): string {
   if (!match) return "";
   return `${match[1]}:${match[2] ?? "00"}`;
 }
+
+function temporalDateParts(value: string): { year: number; month: number; day: number } {
+  const text = formatTemporalInputValue(value, "date");
+  const match = /^(\d{4})-(\d{2})-(\d{2})$/.exec(text);
+  if (!match) {
+    const now = new Date();
+    return { year: now.getFullYear(), month: now.getMonth() + 1, day: now.getDate() };
+  }
+  return { year: Number(match[1]), month: Number(match[2]), day: Number(match[3]) };
+}
+
+function temporalTimeParts(value: string, kind: TemporalCellEditorKind): { hour: number; minute: number; second: number } {
+  const time = kind === "time" ? formatTemporalInputValue(value, "time") || "00:00:00" : formatTemporalInputValue(value, "datetime").split("T")[1] || "00:00:00";
+  const [hour = "00", minute = "00", second = "00"] = time.split(":");
+  return { hour: Number(hour) || 0, minute: Number(minute) || 0, second: Number(second) || 0 };
+}
+
+function daysInMonth(year: number, month: number): number {
+  return new Date(year, month, 0).getDate();
+}
diff --git a/packages/app-tests/dataGridTemporalEditor.test.ts b/packages/app-tests/dataGridTemporalEditor.test.ts
new file mode 100644
index 000000000..1c4290e27
--- /dev/null
+++ b/packages/app-tests/dataGridTemporalEditor.test.ts
@@ -0,0 +1,22 @@
+import { strict as assert } from "node:assert";
+import { test } from "vitest";
+import { stepTemporalInputValue } from "../../apps/desktop/src/lib/dataGridTemporalEditor.ts";
+
+test("steps datetime date and time parts", () => {
+  assert.equal(stepTemporalInputValue("2025-07-01 13:41:49", "datetime", "day", 1), "2025-07-02 13:41:49");
+  assert.equal(stepTemporalInputValue("2025-07-01 13:41:49", "datetime", "month", 1), "2025-08-01 13:41:49");
+  assert.equal(stepTemporalInputValue("2025-07-01 13:41:49", "datetime", "hour", 1), "2025-07-01 14:41:49");
+  assert.equal(stepTemporalInputValue("2025-07-01 13:41:49", "datetime", "minute", -1), "2025-07-01 13:40:49");
+  assert.equal(stepTemporalInputValue("2025-07-01 13:41:49", "datetime", "second", 1), "2025-07-01 13:41:50");
+});
+
+test("clamps stepped dates to the target month", () => {
+  assert.equal(stepTemporalInputValue("2025-01-31", "date", "month", 1), "2025-02-28");
+  assert.equal(stepTemporalInputValue("2024-01-31", "date", "month", 1), "2024-02-29");
+});
+
+test("wraps stepped time values", () => {
+  assert.equal(stepTemporalInputValue("23:59:59", "time", "hour", 1), "00:59:59");
+  assert.equal(stepTemporalInputValue("23:59:59", "time", "minute", 1), "23:00:59");
+  assert.equal(stepTemporalInputValue("23:59:59", "time", "second", 1), "23:59:00");
+});