diff --git a/lib/db.ts b/lib/db.ts
index 09ef79a..333a8e9 100644
--- a/lib/db.ts
+++ b/lib/db.ts
@@ -46,6 +46,11 @@ export function upsertDay(
   hoursLabel?: string,
   specialType?: string
 ) {
+  // For past dates: INSERT new rows freely, but never overwrite existing records.
+  // The API stops returning past dates once they've elapsed, so the DB row is the
+  // permanent historical truth — we must not let a future scrape clobber it.
+  //
+  // For today and future dates: full upsert — the schedule can still change.
   db.prepare(`
     INSERT INTO park_days (park_id, date, is_open, hours_label, special_type, scraped_at)
     VALUES (?, ?, ?, ?, ?, ?)
@@ -54,6 +59,7 @@ export function upsertDay(
       hours_label  = excluded.hours_label,
       special_type = excluded.special_type,
       scraped_at   = excluded.scraped_at
+    WHERE park_days.date >= date('now')
   `).run(parkId, date, isOpen ? 1 : 0, hoursLabel ?? null, specialType ?? null, new Date().toISOString());
 }
 
@@ -160,16 +166,32 @@ export function getMonthCalendar(
   return result;
 }
 
-/** True if the DB already has at least one row for this park+month. */
 const STALE_AFTER_MS = 7 * 24 * 60 * 60 * 1000; // 1 week
 
-/** True if the DB has data for this park+month scraped within the last week. */
+/**
+ * Returns true when the scraper should skip this park+month.
+ *
+ * Two reasons to skip:
+ * 1. The month is entirely in the past — the API will never return data for
+ *    those dates again, so re-scraping wastes a call and risks nothing but
+ *    wasted time. Historical records are preserved forever by upsertDay.
+ * 2. The month was scraped within the last 7 days — data is still fresh.
+ */
 export function isMonthScraped(
   db: Database.Database,
   parkId: string,
   year: number,
   month: number
 ): boolean {
+  // Compute the last calendar day of this month (avoids timezone issues).
+  const daysInMonth = new Date(year, month, 0).getDate();
+  const lastDay = `${year}-${String(month).padStart(2, "0")}-${String(daysInMonth).padStart(2, "0")}`;
+  const today = new Date().toISOString().slice(0, 10);
+
+  // Past month — history is locked in, no API data available, always skip.
+  if (lastDay < today) return true;
+
+  // Current/future month — skip only if recently scraped.
   const prefix = `${year}-${String(month).padStart(2, "0")}`;
   const row = db
     .prepare(