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 40% to 50% chance for below-normal rainfall in June for Trinidad and Tobago.
The Madden–Julian Oscillation (MJO) is forecast to enhance cloudiness and rainfall over the southern Caribbean and Trinidad and Tobago by the second and third 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 negative in June, leading to an increase in sea-surface temperatures and fuelling slow-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 near average, with pockets of warmer than 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 41 years (1981-2021), 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 341.0 millimeters at Crown Point in 1985.
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 April and May, 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 during April and May in urban and built-up areas, especially on hot days.