diff --git a/src/checkTemp.ts b/src/checkTemp.ts
new file mode 100644
index 0000000..8a23ab3
--- /dev/null
+++ b/src/checkTemp.ts
@@ -0,0 +1,8 @@
+/**
+ * Checks if the temperature is within a safe range.
+ * @param temp - temperature in Celsius
+ * @returns true if safe (between 18°C and 30°C), false otherwise
+ */
+export function checkTemperature(temp: number): boolean {
+  return temp >= 18 && temp <= 30;
+}
diff --git a/src/test/checkTemp.tests.ts b/src/test/checkTemp.tests.ts
new file mode 100644
index 0000000..07dabd1
--- /dev/null
+++ b/src/test/checkTemp.tests.ts
@@ -0,0 +1,17 @@
+import { describe, it, expect } from 'vitest';
+import { checkTemperature } from '../checkTemp';
+
+describe('checkTemperature', () => {
+  it('returns true for temperatures within safe range', () => {
+    expect(checkTemperature(20)).toBe(true);
+    expect(checkTemperature(25)).toBe(true);
+  });
+
+  it('returns false for temperatures below safe range', () => {
+    expect(checkTemperature(10)).toBe(false);
+  });
+
+  it('returns false for temperatures above safe range', () => {
+    expect(checkTemperature(35)).toBe(false);
+  });
+});