diff --git a/src/tools/queries/atmosphere.js b/src/tools/queries/atmosphere.js
index 838e4849f..f8e32012c 100644
--- a/src/tools/queries/atmosphere.js
+++ b/src/tools/queries/atmosphere.js
@@ -33,10 +33,12 @@ const round = (value, digits) =>
 
 /**
  * A 2:1 box snapped to 0.25° around the area, moved inside the product's
- * bounds. Returns null when the box would not fit, meaning the whole
- * extent should be shown instead.
+ * bounds. Returns null when no such box covers the whole area (it would not
+ * fit, or the area crosses the antimeridian), meaning the whole extent
+ * should be shown instead.
  */
 export function weatherWindow(area, bounds) {
+  if (area.west > area.east) return null;
   const center = areaCenter(area);
   const halfHeight = Math.max(
     MIN_HALF_HEIGHT_DEGREES,
@@ -57,12 +59,19 @@ export function weatherWindow(area, bounds) {
     snapDown(bounds.north - height),
   );
   const mapBox = { west, south, east: west + width, north: south + height };
-  return mapBox.west >= bounds.west &&
+  const insideProduct =
+    mapBox.west >= bounds.west &&
     mapBox.east <= bounds.east &&
     mapBox.south >= bounds.south &&
-    mapBox.north <= bounds.north
-    ? mapBox
-    : null;
+    mapBox.north <= bounds.north;
+  // Moving the box inside the product can uncover part of the area; only a
+  // box that still holds the whole area (clipped to the product) will do.
+  const coversArea =
+    mapBox.west <= Math.max(area.west, bounds.west) &&
+    mapBox.east >= Math.min(area.east, bounds.east) &&
+    mapBox.south <= Math.max(area.south, bounds.south) &&
+    mapBox.north >= Math.min(area.north, bounds.north);
+  return insideProduct && coversArea ? mapBox : null;
 }
 
 export const getWeatherMap = defineTool({
diff --git a/src/tools/queries/atmosphere.test.mjs b/src/tools/queries/atmosphere.test.mjs
index 8623904ab..cf19d83f3 100644
--- a/src/tools/queries/atmosphere.test.mjs
+++ b/src/tools/queries/atmosphere.test.mjs
@@ -2,6 +2,7 @@ import assert from 'node:assert/strict';
 import test from 'node:test';
 import { composeCatalog, coreTools } from '../index.js';
 import { weatherWindow } from './atmosphere.js';
+import { resolveArea } from '../area.js';
 
 const CONUS = { west: -130, south: 20, east: -60, north: 55 };
 const PNG = Uint8Array.from([0x89, 0x50, 0x4e, 0x47]);
@@ -156,3 +157,18 @@ test('wind is sampled from the model grid at the location', async () => {
     (error) => error.code === 'unavailable',
   );
 });
+
+test('a weather window that cannot cover the area falls back to the whole map', async () => {
+  const world = { west: -180, south: -90, east: 180, north: 90 };
+  // 100 km around 179.8° crosses the antimeridian.
+  const dateline = await resolveArea({ lat: 0, lon: 179.8, radius_km: 100 });
+  assert.equal(weatherWindow(dateline, world), null);
+  // Near a product edge the window moves inside and still covers the area.
+  const conus = { west: -130, south: 20, east: -60, north: 55 };
+  const edge = await resolveArea({ lat: 40, lon: -129.5, radius_km: 50 });
+  const box = weatherWindow(edge, conus);
+  assert.ok(box);
+  assert.ok(box.west <= Math.max(edge.west, conus.west));
+  assert.ok(box.east >= edge.east);
+  assert.ok(box.south <= edge.south && box.north >= edge.north);
+});