In the 2015 census, the population of Tarlac City was 342,493 people, with a density of 1,200 inhabitants per square kilometer or 3,100 inhabitants per square mile.
According to statistics compiled by the Philippine Government, the most dominant religion in the city is Christianity with 73% of the population adhering to the faith.
The majority of Christians are Roman Catholics followed by a large concentration of Iglesia ni Cristo (Church of Christ). Other Christian groups belong to various Protestant denominations. The remaining 27% belong to non-Christian religions such as Islam, etc.
Based on the 1995 census conducted by the NSO within the City of Tarlac, there are three major dialects generally spoken by the people, namely: Pampango, Tagalog and Ilocano. Pampango or Kapampangan represent 75.22%, Tagalog, 14.58%, Ilocano, 8.55%, and the remaining 1.65% constitute other dialects such as Pangasinense, Visayan, Bicolano, etc.
The October 2000 survey conducted by the NSO within the City of Tarlac states that out of the 164,000 household population aged 15 years old and above, 60.37% are in the labor force, while 39.63% are not. Out of those in the labor force, 54.88% are employed, while 5.49% are unemployed, having a 90.50% employment rate and 9.50% unemployment with a visible underemployment rate of 0.70%. Fifty percent (50%) of the 90,000 household populations are mostly employed in the service industry, while 34.44% are in various industries and 15.56% are in the agricultural industry.
The City of Tarlac is approximately 24 meters (79 ft) above sea level on some parts but reach up to 50 meters (160 ft) on large western portions. Its total area is about 274.7 km², composed of seventy-six (76) barangays.
The physical terrain of the City of Tarlac is generally flat with slightly rolling to mountainous on the western part. The whole city is traversed by the Tarlac River system.
Being basically an agriculture town, a big percentage of the land is devoted to agricultural production and thus scattered in all slope ranges. Slope ranges are directly proportional to erosion potential. The lower the slope, the lower its susceptibility to erosion.
The climate of Tarlac resembles closely that of the surrounding provinces, Nueva Ecija, Pampanga, and Pangasinan. It has two distinct seasons: wet and dry. The months of November to April are generally dry while the rest of the year is rainy season. Tarlac receives its continuous rainfall during the southwest monsoon period from June to November, which corresponds with the wet season. The northeast monsoon period from the months of November to May constitute the dry season.
Tarlac City is best to be visited from November to February for its festivities such as Halloween, Christmas, and the City Fiesta. The weather during this period is relatively cool. Holy Week is also one of the best times to experience tradition and culture of the city in its observance of the Pasion of Christ.