Answer
Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Dear brother, thank you for your question and for your interest in performing fasting, the fourth pillar of Islam.
As for your question, you should follow the local community you are living in. However, if they are fasting according to your local timing and you find it too hard to fast, you skip the fast and make up for it later.
In his response to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states,
If the Muslim community decides to go by the standard time of Makkah or Madinah, they are free to do so, as ruled by some eminent scholars.
If, however, they do not choose to follow the above standard; rather they insist on following the signs of dawn and sunset, then you should try your best to fast with them.
If you find it extremely hard, you are allowed to skip the fast and make up for it later by fasting when the hours of the day are shorter.
Allah Almighty knows best.