diff --git a/src/weather/Provider.zig b/src/weather/Provider.zig
index d9a3852..490428e 100644
--- a/src/weather/Provider.zig
+++ b/src/weather/Provider.zig
@@ -23,8 +23,8 @@ pub const VTable = struct {
 
 pub fn fetch(self: WeatherProvider, allocator: std.mem.Allocator, coords: Coordinates) !types.WeatherData {
     // Generate cache key from coordinates
-    const cache_key = try std.fmt.allocPrint(allocator, "{d:.4},{d:.4}", .{ coords.latitude, coords.longitude });
-    defer allocator.free(cache_key);
+    var buf: [256]u8 = undefined;
+    const cache_key = try std.fmt.bufPrint(&buf, "{d:.4},{d:.4}", .{ coords.latitude, coords.longitude });
 
     // Check cache first
     if (self.cache.get(cache_key)) |cached_raw|