September weather forecast
Saint-Marc, Haiti

As autumn approaches, September brings a cool-down in temperature and sea temperature from its peak in August in Saint-Marc. On the contrary, rainfall slightly rises to 101mm, marking September as the month with the second-highest rainfall. With fewer daylight hours and fewer sunshine days, the weather in September can be unpredictable, making it ideal for those looking to experience the variety of Saint-Marc’s tropical climate.

Temperature

Saint-Marc, Haiti, marks the onset of September with an average high-temperature of a warm 29.8°C, subtly divergent from August's 30.4°C. Throughout September, an average nighttime temperature of 23.1°C is experienced in Saint-Marc.

Heat index

For most parts of September, the heat index is calculated to be a very hot 37°C. Ensure additional precautions, heat exhaustion and heat cramps may be expected. Heatstroke could occur from sustained activity.
It is worth noting that heat index values are gauged for conditions in the shade and light breezes. Facing direct sunlight may hike up the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. Metabolic differences, pregnancy status, and the level of physical activity are additional factors influencing an individual's weather perception. Direct sunlight exposure should be noted as it has the potential to increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Youngsters typically face more danger than adults since they sweat less. Their larger skin surface compared to their small bodies and heightened heat production from their activities augment their vulnerability.
One way the human body deals with excessive warmth is by perspiring and allowing sweat to evaporate. Relative humidity in excess curtails evaporation, therefore reducing heat dissipation from the body, leading to feelings of excess heat. Elevated heat gain compared to the body's release capability poses risks of dehydration and potential overheating.

Humidity

In September, the average relative humidity is 79%.

Rainfall

In Saint-Marc, Haiti, during September, the rain falls for 23.6 days and regularly aggregates up to 101mm of precipitation. Throughout the year, there are 219.6 rainfall days, and 736mm of precipitation is accumulated.

Sea temperature

The month with the warmest seawater is September, with an average sea temperature of 29.9°C.
Note: For any water activity, having surface water temperatures from 25°C to 29°C is considered outstanding and highly delightful for lengthened periods.

Daylight

In Saint-Marc, Haiti, the average length of the day in September is 12h and 14min.
On the first day of September in Saint-Marc, sunrise is at 06:35 and sunset at 19:05. On the last day of the month, sunrise is at 06:41 and sunset at 18:40 EDT.

Sunshine

In September, the average sunshine is 10.1h.

UV index

The months with the highest UV index are April through September, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for the average person.
Note: The daily high UV index of 7 in September translates into this advice:
Avoid excessive sunlight. Those with lighter skin may experience burning in less than 20 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat. Be attentive! The UV exposure is heightened with reflections from sand and water.