diff --git a/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts b/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts
index c789d5505df8..1af53b2b913a 100644
--- a/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts
+++ b/packages/angular_devkit/build_angular/src/webpack/configs/styles.ts
@@ -148,6 +148,9 @@ export function getStylesConfig(wco: WebpackConfigOptions): webpack.Configuratio
       );
     }
     if (tailwindPackagePath) {
+      if (process.env['TAILWIND_MODE'] === undefined) {
+        process.env['TAILWIND_MODE'] = buildOptions.watch ? 'watch' : 'build';
+      }
       extraPostcssPlugins.push(require(tailwindPackagePath)({ config: tailwindConfigPath }));
     }
   }