The Azores have the warmest winters in Europe. During summer the lag is somewhat lower, with August being the warmest month, though September is usually as warm or warmer than July. There has never been a frost, snowfall, freeze or even temperatures below recorded at sea level on any of the islands. The coldest weather in winter usually comes from northwesterly air masses originating from Labrador in Canada. However, since those air masses are warmed up as they pass across the warmer Atlantic Ocean, temperatures by day even then exceed . The westernmost islands of the archipelago, namely Flores and Corvo, get the strongest maritime moderation and the most rainfall since both are right on the Gulf Stream waters.