Hotter still is the core. In the sun this is thought to be 10 - 20 million degrees. These temperatures are due to the pressure caused by gravity trying to compress the star. It has to be this temperature for fusion of hydrogen to take place. Once fusion starts in a young star this adds to the temperature to ensure that fusion continues.
Weather in Lisbon in September. The average maximum daytime temperature in Lisbon in September is a warm 27Â°C (81Â°F) with low heat & humidity. There are usually 9 hours of bright sunshine each day, which represents 68% of the 12 hours of daylight. The average sea temperature in and around Lisbon in September is 19Â°C (66Â°F). Expect 26mm (1.0 inches) of rainfall across the whole of September with 6 days with some rain falling. Maximum UV levels will be high (6 UV index) at midday when the skies are clear.
The average temperature in Lisbon in February is quite mild at 12.3 Â°C (54.14 Â°F). Afternoons can be very mild with average high temperatures reaching 15.6 Â°C (60.1 Â°F). Overnight temperatures are generally a little cool with an average low of 9 Â°C (48.2 Â°F). The variation/ range of daily average temperatures in February is 6.6 Â°C (11.9 Â°F). The weather in February is hardly dry with rain occasionally. Circa 111mm (4.4in) of H2O is transfered across an average of 12 days.