diff --git a/test/microwaveprop/weather/hrrr_client_test.exs b/test/microwaveprop/weather/hrrr_client_test.exs
index 4a7a2261..e1af658d 100644
--- a/test/microwaveprop/weather/hrrr_client_test.exs
+++ b/test/microwaveprop/weather/hrrr_client_test.exs
@@ -1,5 +1,5 @@
 defmodule Microwaveprop.Weather.HrrrClientTest do
-  use ExUnit.Case, async: true
+  use ExUnit.Case, async: false
 
   alias Microwaveprop.Weather.HrrrClient
 
diff --git a/test/microwaveprop/weather_test.exs b/test/microwaveprop/weather_test.exs
index ec2f648d..91e3f8bb 100644
--- a/test/microwaveprop/weather_test.exs
+++ b/test/microwaveprop/weather_test.exs
@@ -1327,12 +1327,25 @@ defmodule Microwaveprop.WeatherTest do
   end
 
   describe "available_weather_valid_times/0" do
+    # Other async test modules insert HrrrProfile rows with
+    # is_grid_point: true. Wipe them so the "empty DB" assertion
+    # doesn't flake.
+    setup do
+      Repo.delete_all(from(h in HrrrProfile, where: h.is_grid_point == true))
+      :ok
+    end
+
     test "returns an empty list when no scores are stored" do
       assert Weather.available_weather_valid_times() == []
     end
   end
 
   describe "latest_grid_valid_time/0" do
+    setup do
+      Repo.delete_all(from(h in HrrrProfile, where: h.is_grid_point == true))
+      :ok
+    end
+
     test "returns nil when no scores are stored" do
       assert Weather.latest_grid_valid_time() == nil
     end
diff --git a/test/microwaveprop_web/controllers/contact_map_controller_test.exs b/test/microwaveprop_web/controllers/contact_map_controller_test.exs
index 1567765b..f1d69608 100644
--- a/test/microwaveprop_web/controllers/contact_map_controller_test.exs
+++ b/test/microwaveprop_web/controllers/contact_map_controller_test.exs
@@ -2,12 +2,21 @@ defmodule MicrowavepropWeb.ContactMapControllerTest do
   use MicrowavepropWeb.ConnCase, async: false
 
   alias Microwaveprop.Cache
+  alias MicrowavepropWeb.Api.RateLimiter
 
   setup do
     # The controller caches a gzipped payload under a module-level key —
     # clear it between tests so gzip vs identity requests don't reuse
     # each other's output.
     Cache.invalidate({MicrowavepropWeb.ContactMapController, :gzipped_payload})
+
+    # The controller uses a fixed-window ETS rate limiter. Since every
+    # test request shares the same client IP, accumulated counters from
+    # prior tests (or async tests) can exhaust the bucket and trigger a
+    # 429 before this test even runs. Reset the table per-test so each
+    # describe/3 group starts with a clean slate.
+    RateLimiter.reset()
+
     :ok
   end