מזג האוויר בקוסומל בספטמבר

Forum posters describe September as hot, humid and genuinely buggy - warmer and more humid even than late May by some accounts - and squarely inside peak hurricane season, with trip insurance a standard recommendation given the real (if statistically low in any given week) storm risk. Rain typically shows up as a short, 10-30 minute shower followed by a return to sun rather than an all-day washout, though posters note humidity builds noticeably on windless days. The clear upside repeatedly mentioned: September marks the start of the island's slow season, with noticeably fewer tourists, still-warm water and mild, predictable currents - a real trade-off for visitors willing to accept the heat, bugs and hurricane-season backdrop.

Regulars are specific this month splits into two real halves - the beginning typically drier, while the probability of rain increases toward the end as the wet season gets underway, most storms lasting just 15 to 30 minutes and highly localized rather than island-wide. Our row backs that hot, genuinely wet read, 32.7C reading as a scorching 37C, over 24C nights feeling 26C, with 65.3mm of rain across 10.4 days and humidity at 78 percent. Regulars are consistent forecasts here aren't reliable, it can rain somewhere on the island while another spot stays completely dry, so a poor-looking forecast is no reason to change plans. Warm enough for swimming remains the consistent read regardless of any given day's rain chances. The sea sits at a bath-warm 28.6C. The record: 11.7 hours of sun, a 26 kph wind and AQI 46.

Cozumel-forum threads on July weather are direct: plenty hot and humid, daytime temperatures near the mid-90s Fahrenheit with humidity that regulars describe as running close to total, muggy even in the earliest morning hours before the sun is properly up. Rain is real this time of year, marking the start of the wet season, but posters are consistent that a full washed-out day is uncommon - more typical is a shower on one side of the island while the other stays dry, or thirty minutes of rain followed by hours of sun. A handful of visits do land on the other extreme, a full day or week of rain, but regulars call that the exception rather than what to expect. Multiple posters who've visited Cozumel dozens of times across June and July say they've almost always had a great trip regardless of the heat and humidity. The record: a scorching 33.4C by day feeling like a punishing 39C, 24.6C nights, 68mm across 12.4 days, 79 percent humidity, a 29.7C sea and 11.8 hours of sun.

Cozumel-forum threads explaining what a norte is lay out January's real rhythm: a typical day is sunny and warm, but cold fronts roll through roughly every seven to ten days, dropping daytime temperatures into the mid-20s Celsius and nights to around 15C, with strong wind and precipitation riding in alongside each one. Fronts usually last two to three days, occasionally longer, and are frequent enough between November and March that dive trips need a backup plan - a norte can close the port to smaller boats, though bigger operators often still run. Regulars still call January genuinely pleasant on balance: low humidity for the island, easy sunny stretches between fronts. The record: 28.1C days feeling like 29C, 20.4C nights, 66mm across 13.8 days, a 27.3C sea and wind averaging 28 km/h - warm and breezy most days, with real cold-front interruptions built into the month.

April is a diving month on Cozumel and the forum's reports are unusually specific: visibility easily over 100 feet, one windy day in a week, and rain never lasting more than a few minutes. Their standing note about forecasts is that you should not trust them here - a week predicted wet typically delivers a few brief showers and sun most of the time, and a shower rarely covers the whole island, so you can often drive out of it. Our row agrees at 29.2mm across 6.3 days. The one April caveat is current, which runs more erratically in March and April than later; experienced divers are fine and several say they came to enjoy it. April is also the month for eagle rays. The record: 31.8C days that feel like 35C, 22.4C nights, a 27.4 kph wind and a 27.6C sea.