diff --git a/packages/grpc-js/test/test-weighted-round-robin.ts b/packages/grpc-js/test/test-weighted-round-robin.ts
index 3016cb8e4..3dc7baa9f 100644
--- a/packages/grpc-js/test/test-weighted-round-robin.ts
+++ b/packages/grpc-js/test/test-weighted-round-robin.ts
@@ -28,20 +28,19 @@ const protoFile = path.join(__dirname, 'fixtures', 'echo_service.proto');
 const EchoService = (loadProtoFile(protoFile) as unknown as ProtoGrpcType).EchoService;
 
 function makeNCalls(client: EchoServiceClient, count: number): Promise<{[serverId: string]: number}> {
-  return new Promise((resolve, reject) => {
-    const result: {[serverId: string]: number} = {};
-    function makeOneCall(callsLeft: number) {
-      if (callsLeft <= 0) {
-        resolve(result);
-      } else {
+  const result: {[serverId: string]: number} = {};
+  const promises: Promise<void>[] = [];
+  for (let index = 0; index < count; index++) {
+    promises.push(
+      new Promise<void>((resolve, reject) => {
         const deadline = new Date();
-        deadline.setMilliseconds(deadline.getMilliseconds() + 100);
-        const call= client.echo({}, {deadline}, (error, value) => {
+        deadline.setSeconds(deadline.getSeconds() + 2);
+        const call = client.echo({}, {deadline}, (error, value) => {
           if (error) {
             reject(error);
             return;
           }
-          makeOneCall(callsLeft - 1);
+          resolve();
         });
         call.on('metadata', metadata => {
           const serverEntry = metadata.get('server');
@@ -53,9 +52,60 @@ function makeNCalls(client: EchoServiceClient, count: number): Promise<{[serverI
             result[serverId] += 1;
           }
         });
+      })
+    );
+  }
+  return Promise.all(promises).then(() => result);
+}
+
+function warmupAllServers(client: EchoServiceClient, serverCount = 2): Promise<void> {
+  const seenServers = new Set<string>();
+  const deadline = new Date();
+  deadline.setSeconds(deadline.getSeconds() + 5);
+
+  return new Promise<void>((resolve, reject) => {
+    function sendNextCall() {
+      if (seenServers.size >= serverCount) {
+        resolve();
+        return;
       }
+      const call = client.echo({}, {deadline}, error => {
+        if (error) {
+          reject(error);
+          return;
+        }
+        sendNextCall();
+      });
+      call.on('metadata', metadata => {
+        const serverEntry = metadata.get('server');
+        if (serverEntry.length > 0) {
+          const serverId = serverEntry[0] as string;
+          if (serverId) {
+            seenServers.add(serverId);
+          }
+        }
+      });
     }
-    makeOneCall(count);
+    sendNextCall();
+  });
+}
+
+function waitForPickerUpdate(client: EchoServiceClient, timeoutMs = 2000): Promise<void> {
+  const internalChannel = (client.getChannel() as any).internalChannel;
+  const initialPicker = internalChannel.currentPicker;
+  const startTime = Date.now();
+
+  return new Promise<void>((resolve, reject) => {
+    const checkPicker = () => {
+      if (internalChannel.currentPicker !== initialPicker) {
+        resolve();
+      } else if (Date.now() - startTime > timeoutMs) {
+        reject(new Error('Timed out waiting for WeightedRoundRobinPicker to update'));
+      } else {
+        setTimeout(checkPicker, 10);
+      }
+    };
+    checkPicker();
   });
 }
 
@@ -72,13 +122,28 @@ function createClient(ports: number[], serviceConfig: grpc.ServiceConfig) {
   return new EchoService(`ipv4:${ports.map(port => `127.0.0.1:${port}`).join(',')}`, grpc.credentials.createInsecure(), {'grpc.service_config': JSON.stringify(serviceConfig)});
 }
 
+function waitForClientReady(client: EchoServiceClient): Promise<void> {
+  return new Promise((resolve, reject) => {
+    const deadline = new Date();
+    deadline.setSeconds(deadline.getSeconds() + 5);
+    client.waitForReady(deadline, error => {
+      if (error) {
+        reject(error);
+      } else {
+        resolve();
+      }
+    });
+  });
+}
+
 function asyncTimeout(delay: number): Promise<void> {
   return new Promise(resolve => {
     setTimeout(resolve, delay);
   });
 }
 
-describe('Weighted round robin LB policy', () => {
+describe('Weighted round robin LB policy', function () {
+  this.timeout(process.platform === 'win32' ? 10000 : 5000);
   describe('Config parsing', () => {
     it('Should have default values with an empty object', () => {
       const config = WeightedRoundRobinLoadBalancingConfig.createFromJson({});
@@ -261,7 +326,8 @@ describe('Weighted round robin LB policy', () => {
     it('Should evenly balance among endpoints with no weight', async () => {
       const serviceConfig = createServiceConfig({});
       client = createClient([port1, port2], serviceConfig);
-      await makeNCalls(client, 10);
+      await waitForClientReady(client);
+      await warmupAllServers(client);
       const result = await makeNCalls(client, 30);
       assert(Math.abs(result['1'] - result['2']) < 3, `server1: ${result['1']}, server2: ${result[2]}`);
     });
@@ -271,12 +337,13 @@ describe('Weighted round robin LB policy', () => {
         weight_update_period: '0.1s'
       });
       client = createClient([port1, port2], serviceConfig);
+      await waitForClientReady(client);
       server1Metrics.qps = 3;
       server1Metrics.utilization = 1;
       server2Metrics.qps = 1;
       server2Metrics.utilization = 1;
-      await makeNCalls(client, 10);
-      await asyncTimeout(200);
+      await warmupAllServers(client);
+      await waitForPickerUpdate(client);
       const result = await makeNCalls(client, 40);
       assert(Math.abs(result['1'] - 30) < 3, `server1: ${result['1']}, server2: ${result['2']}`);
     });
@@ -324,14 +391,15 @@ describe('Weighted round robin LB policy', () => {
         error_utilization_penalty: 1
       });
       client = createClient([port1, port2], serviceConfig);
+      await waitForClientReady(client);
       server1Metrics.qps = 2;
       server1Metrics.utilization = 1;
       server1Metrics.eps = 0;
       server2Metrics.qps = 2;
       server2Metrics.utilization = 1;
       server2Metrics.eps = 2;
-      await makeNCalls(client, 10);
-      await asyncTimeout(100);
+      await warmupAllServers(client);
+      await waitForPickerUpdate(client);
       const result = await makeNCalls(client, 30);
       assert(Math.abs(result['1'] - 20) < 3, `server1: ${result['1']}, server2: ${result['2']}`);
     });
@@ -411,7 +479,8 @@ describe('Weighted round robin LB policy', () => {
         blackout_period: '0.01s'
       });
       client = createClient([port1, port2], serviceConfig);
-      await makeNCalls(client, 10);
+      await waitForClientReady(client);
+      await warmupAllServers(client);
       const result = await makeNCalls(client, 30);
       assert(Math.abs(result['1'] - result['2']) < 3, `server1: ${result['1']}, server2: ${result[2]}`);
     });
@@ -423,12 +492,13 @@ describe('Weighted round robin LB policy', () => {
         weight_update_period: '0.1s'
       });
       client = createClient([port1, port2], serviceConfig);
+      await waitForClientReady(client);
       server1MetricRecorder.setQpsMetric(3);
       server1MetricRecorder.setApplicationUtilizationMetric(1);
       server2MetricRecorder.setQpsMetric(1);
       server2MetricRecorder.setApplicationUtilizationMetric(1);
-      await makeNCalls(client, 10);
-      await asyncTimeout(200);
+      await warmupAllServers(client);
+      await waitForPickerUpdate(client);
       const result = await makeNCalls(client, 40);
       assert(Math.abs(result['1'] - 30) < 3, `server1: ${result['1']}, server2: ${result['2']}`);
     });