diff --git a/api/v1_challenges_info.go b/api/v1_challenges_info.go
index 4b78a194..b5571ce2 100644
--- a/api/v1_challenges_info.go
+++ b/api/v1_challenges_info.go
@@ -1,7 +1,6 @@
 package api
 
 import (
-	"fmt"
 	"time"
 
 	"github.com/gofiber/fiber/v2"
@@ -25,16 +24,25 @@ type ChallengeInfo struct {
 }
 
 func getWeeklyPoolWindowStart() time.Time {
-	now := time.Now().UTC()
+	return weeklyPoolWindowStartAt(time.Now())
+}
 
-	if now.Weekday() == time.Monday && now.Hour() < 16 {
-		year, month, day := now.AddDate(0, 0, -7).Date()
-		return time.Date(year, month, day, 16, 0, 0, 0, time.UTC)
-	} else {
-		// get monday of this week
-		year, month, day := now.AddDate(0, 0, -int(now.Weekday())+1).Date()
-		return time.Date(year, month, day, 16, 0, 0, 0, time.UTC)
+// weeklyPoolWindowStartAt returns the most recent Monday 16:00 UTC at or
+// before `now`: the instant the current weekly reward pool opened.
+//
+// Go numbers Sunday as 0, so the naive "subtract Weekday, add one" walk to
+// Monday landed on the *following* Monday all day Sunday, putting the window
+// start in the future and reporting the full pool as remaining every Sunday.
+func weeklyPoolWindowStartAt(now time.Time) time.Time {
+	now = now.UTC()
+	daysSinceMonday := (int(now.Weekday()) + 6) % 7 // Monday=0 ... Sunday=6
+	year, month, day := now.AddDate(0, 0, -daysSinceMonday).Date()
+	start := time.Date(year, month, day, 16, 0, 0, 0, time.UTC)
+	if now.Before(start) {
+		// Monday before 16:00: still last week's pool.
+		start = start.AddDate(0, 0, -7)
 	}
+	return start
 }
 
 func (app *ApiServer) v1ChallengesInfo(c *fiber.Ctx) error {
@@ -44,7 +52,6 @@ func (app *ApiServer) v1ChallengesInfo(c *fiber.Ctx) error {
 	}
 
 	weeklyPoolWindowStart := getWeeklyPoolWindowStart()
-	fmt.Println("weeklyPoolWindowStart", weeklyPoolWindowStart)
 
 	sql := `
 	  SELECT
diff --git a/api/v1_challenges_info_test.go b/api/v1_challenges_info_test.go
index 782846c5..d54895fa 100644
--- a/api/v1_challenges_info_test.go
+++ b/api/v1_challenges_info_test.go
@@ -72,3 +72,30 @@ func TestV1ChallengesInfoInvalidWeeklyPoolMinAmount(t *testing.T) {
 		"error": "weekly_pool_min_amount is invalid",
 	})
 }
+
+func TestWeeklyPoolWindowStartAt(t *testing.T) {
+	utc := func(y int, m time.Month, d, h int) time.Time {
+		return time.Date(y, m, d, h, 0, 0, 0, time.UTC)
+	}
+	// 2026-09-07 is a Monday.
+	thisMonday := utc(2026, time.September, 7, 16)
+	lastMonday := utc(2026, time.August, 31, 16)
+
+	cases := []struct {
+		name string
+		now  time.Time
+		want time.Time
+	}{
+		{"Monday before 16:00 is still last week", utc(2026, time.September, 7, 15), lastMonday},
+		{"Monday at 16:00 opens the week", thisMonday, thisMonday},
+		{"Wednesday", utc(2026, time.September, 9, 12), thisMonday},
+		{"Saturday", utc(2026, time.September, 12, 23), thisMonday},
+		{"Sunday (Go weekday 0) is the end of the week, not the start of the next", utc(2026, time.September, 13, 21), thisMonday},
+		{"Sunday just before the next Monday", utc(2026, time.September, 13, 23), thisMonday},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			assert.Equal(t, tc.want, weeklyPoolWindowStartAt(tc.now))
+		})
+	}
+}