Helpful tip for Brazilian coders in need of timezone information. Here follows the list of timezones used by each state (source: https://en.wikipedia.org/wiki/Time_in_Brazil):
$timezones = array(
'AC' => 'America/Rio_branco', 'AL' => 'America/Maceio',
'AP' => 'America/Belem', 'AM' => 'America/Manaus',
'BA' => 'America/Bahia', 'CE' => 'America/Fortaleza',
'DF' => 'America/Sao_Paulo', 'ES' => 'America/Sao_Paulo',
'GO' => 'America/Sao_Paulo', 'MA' => 'America/Fortaleza',
'MT' => 'America/Cuiaba', 'MS' => 'America/Campo_Grande',
'MG' => 'America/Sao_Paulo', 'PR' => 'America/Sao_Paulo',
'PB' => 'America/Fortaleza', 'PA' => 'America/Belem',
'PE' => 'America/Recife', 'PI' => 'America/Fortaleza',
'RJ' => 'America/Sao_Paulo', 'RN' => 'America/Fortaleza',
'RS' => 'America/Sao_Paulo', 'RO' => 'America/Porto_Velho',
'RR' => 'America/Boa_Vista', 'SC' => 'America/Sao_Paulo',
'SE' => 'America/Maceio', 'SP' => 'America/Sao_Paulo',
'TO' => 'America/Araguaia',
);