The Trinidad and Tobago Meteorological Service (TTMS) is forecasting near- to above-average rainfall totals across much of the country for June 2023 in their updated outlook, issued on May 12th, 2023.
June is generally the first month of the annual Wet Season in Trinidad and Tobago. Early-season tropical waves commonly affect the country every five to seven days. Rainfall may occasionally be influenced by the Intertropical Convergence Zone or an early-season Atlantic tropical cyclone.
In the latest outlook, the TTMS says that there is a 36% to 57% chance for above-normal rainfall in June for Trinidad and Tobago. There is also a 27% to 58% chance of wetter-than-usual conditions across western Trinidad.
The Madden–Julian Oscillation (MJO) is forecast to enhance cloudiness and rainfall over the southern Caribbean and Trinidad and Tobago by the first and second weeks of June.
Additionally, since April, the North Atlantic Oscillation (NAO) has alternated positive and negative phases. A positive NAO increases the chance for strengthened trade winds, enhancing the cooling of sea surface temperatures in the North Atlantic. However, the NAO is forecast to be positive in June, leading to a possible decrease in sea-surface temperatures and fast-moving showers.
Currently, sea surface temperatures in waters surrounding Trinidad and Tobago, including waters to the east of the eastern Caribbean to the West Coast of Northern Africa, are mostly above average, with pockets of near-average temperatures.
June is the second wettest month of the year for Trinidad, and the fifth wettest month for Tobago, with an average (1991-2020) monthly rainfall of 243.3 millimeters at Piarco, Trinidad, and 157.3 millimeters at Crown Point, Tobago.
In the last 42 years (1981-2022), the driest June recorded 113.1 millimeters at Piarco and 50.3 millimeters at Crown Point in 2009 and 1981, respectively. The wettest June in the same period recorded 457.1 millimeters at Piarco in 1983 and 377.4 millimeters at Crown Point in 1992.
Temperature-wise, the TTMS is still forecasting above-average temperatures not only for June but over the next several months through the Wet Season.
During June, Trinidad and Tobago can experience hot days (days with maximum temperatures reaching or exceeding 34.0°C in Trinidad and 32.0°C in Tobago), which can likely develop into short-duration hot spells (periods of at least five consecutive hot days). Excessive heat build-up is highly likely in urban and built-up areas, especially on hot days.
