Chetumal weather in September
In September, Chetumal has daytime highs averaging 30 °C, nights around 25 °C, with 25 wet days, and a sea temperature of 30 °C. Figures are 1991–2020 climate normals.
- 30.4°C Average high
- 24.7°C Average low
- 25days Wet days
- 188mm Rainfall
- 29.9°C Sea temperature
- 12h Daylight
Daily temperatures through September
How September develops
Averages for the first, middle and last part of the month, from daily 1991–2020 normals. Chance of rain is the share of years in which that calendar day recorded more than 1 mm.
| Days | Avg high | Avg low | Chance of rain |
|---|---|---|---|
| 1–10 September | 30.8 °C | 24.9 °C | 76 % |
| 11–20 September | 30.6 °C | 24.8 °C | 83 % |
| 21–30 September | 30.0 °C | 24.4 °C | 89 % |
- Rain is most likely over days 21–30 of September (89 % of days) and least likely over days 1–10 (76 %).
What to expect
| Measure | Typical September | Share of the month |
|---|---|---|
| Days above 25 °C | 30 of 30 | 100 % |
| Days above 30 °C | 20 of 30 | 65 % |
| Days below 0 °C | 0 of 30 | 0 % |
| Days with more than 1 mm rain | 25 of 30 | 83 % |
Conditions in September
| Measure | Average |
|---|---|
| Mean temperature | 27 °C |
| Record high (1991–2020) | 35 °C |
| Record low (1991–2020) | 22 °C |
| Relative humidity | 85 % |
| Wind speed | 15 km/h |
| Cloud cover | 69 % |
Where Chetumal ranks in September
| Ranking | Position | Value |
|---|---|---|
| Warmest sea temperatures in the world in September | 32ndof 50 | 30 °C |
September compared with the months around it
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| July | 30.6 °C | 122 mm | 60 % |
| August | 31.0 °C | 156 mm | 60 % |
| September | 30.4 °C | 188 mm | 69 % |
| October | 29.1 °C | 189 mm | 65 % |
| November | 27.8 °C | 99 mm | 51 % |
See all twelve months for Chetumal
- September is the 5th warmest month here.
- It is the 10th driest month of the year.
- It ranks 11th for least cloud cover.
- Days last about 12 hours from sunrise to sunset.
- It rains on 25 of 30 days — 83 % of the month.
- Nights are about 5.8 °C cooler than the middle of the day.
- The hottest September day on record since 1991 reached 35 °C, 5.0 °C above the usual daytime high.
- Beach score: 62 / 100 — see how this is calculated.
Nearby destinations in September
| Destination | Avg high | Wet days | Sea |
|---|---|---|---|
| Chetumal | 30 °C | 25 | 30 |
| Belmopan | 30 °C | 25 | – |
| Campeche | 32 °C | 23 | 30 |
| Mérida | 33 °C | 19 | – |
| Cancún | 29 °C | 24 | 29 |
| San Pedro Sula | 31 °C | 27 | – |
| La Ceiba | 29 °C | 27 | 30 |
| La Ceiba | 29 °C | 27 | 30 |
| Ciudad del Carmen | 31 °C | 25 | 30 |
QuestionsSeptember in Chetumal, answered
How warm is Chetumal in September?
Daily highs average 30 °C and nights fall to about 25 °C, a spread of 5.8 °C between afternoon and dawn. That makes September the 5th warmest month of the year here.
Does it rain much in Chetumal in September?
September averages 188 mm of rain, spread over about 25 of the 30 days — 83 % of the month. Cloud cover averages 69 % of the sky.
Is the sea warm enough to swim in September?
The sea averages 30 °C off Chetumal in September. Most people find water below 20 °C bracing and above 25 °C comfortable for a long swim; this figure is a monthly surface average, so a sheltered bay on a still afternoon can be warmer.
How long are the days in September?
Chetumal averages 12 hours between sunrise and sunset in September. Day length is computed from latitude and date, so it is exact rather than modelled — but it says nothing about how much of that time is sunny.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: daylight hours, beach and comfort scores, monthly rankings, threshold day counts, chance of a wet day by date, ten-day averages within the month. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.