diff --git a/static/js/weather-app.js b/static/js/weather-app.js
index d43417d..04c5bb0 100644
--- a/static/js/weather-app.js
+++ b/static/js/weather-app.js
@@ -16,9 +16,13 @@ const WeatherMap = {
         this.initializeMap(tiandituKey);
         this.setupEventListeners();
         this.setupTileControls();
-        // 默认不显示（需用户选择），但准备好默认索引
+        // 默认叠加：组合反射率（radar），并准备默认索引
         this.tileZ = 7; this.tileY = 40; this.tileX = 102;
-        this.tileProduct = 'none';
+        this.tileProduct = 'radar';
+        const prodSel = document.getElementById('tileProduct');
+        if (prodSel) prodSel.value = 'radar';
+        // 触发首次加载
+        try { this.reloadTileTimesAndShow(); } catch(e) { console.warn('init tiles load failed', e); }
     },
 
     // 初始化图层