diff --git a/firmware/sensor_wind.ino b/firmware/sensor_wind.ino
index b354b99..080329d 100644
--- a/firmware/sensor_wind.ino
+++ b/firmware/sensor_wind.ino
@@ -5,19 +5,25 @@
 #define WIND_DEFAULT_MEAS_INIT 255
 
 volatile unsigned int anemometerRotations  = 0;
-uint32_t     start_meas_wind_time = 0;
-int          interruptNumber;
+volatile uint32_t start_meas_wind_time = 0;
+int interruptNumber;
 
 #ifndef SENSOR_WIND_NO_ISR
 void ICACHE_RAM_ATTR _anemometerInterrupt()
 {
+  if ((start_meas_wind_time + (WIND_SENSOR_MEAS_TIME_S * 1000)) <= millis())
+  {
+    // measurement already done, prevent read of further rotations
+    return;
+  }
+
   anemometerRotations++;
 #ifdef DEBUG
   Serial.print("*");
   debug("*");
 #endif
 }
-#endif
+#endif // end of if not defined SENSOR_WIND_NO_ISR
 
 float wind_speed()
 {
@@ -30,9 +36,9 @@ float wind_speed()
 
 void start_measure_wind()
 {
-  start_meas_wind_time = millis();
   anemometerRotations = 0;
 #ifndef SENSOR_WIND_NO_ISR
+  start_meas_wind_time = millis();
   interruptNumber = digitalPinToInterrupt(ANEMOMETER_PIN);
   attachInterrupt(interruptNumber, _anemometerInterrupt, FALLING);
 #endif