Het weer in Barreirinhas (Lençóis Maranhenses) in september

Barreirinhas-forum threads on late-September visits to Lencois Maranhenses call this the tail end of the park's strongest lagoon window, the May-through-September stretch when most rainwater pools between the dunes sit full and swimmable. Posters flag a real quirk, one visitor reporting an unusually intense stretch that left several lagoons already drained by early September, with local guides suggesting June or July as a genuinely safer bet for guaranteed pools. Regulars are consistent conditions vary year to year, a call to a local operator before booking standing advice over relying on the calendar. Posters describe skies as reliably clear this time of year, sunscreen and water essential regardless of dates. Regulars call the dune-and-lagoon landscape worth the trip even if fewer pools are full than hoped. Posters recommend an early start to beat both heat and crowds. The record: 31.9C days feeling like a punishing 35C, 25.5C nights, a low 72 percent humidity and 11.3 hours of sun.

Barreirinhas-forum reviews on a July visit describe the Lencois Maranhenses lagoons as genuinely at their fullest, one reviewer who visited twice in July calling the landscape stunning and the pools good for swimming. Regulars call June through July genuinely the peak window, several posters naming temperatures in the low thirties Celsius with almost no rain by this point as the real payoff after the wetter months. Posters call October and November genuinely the opposite extreme, several regulars naming most pools dried up by then as why timing matters so much. Regulars call the constantly shifting dunes genuinely comfortable underfoot, several threads naming the wind keeping sand from holding heat as a small real detail. Posters recommend targeting June through July specifically for full lagoons, several regulars calling this standard advice for anyone planning around the park's namesake pools. The record: 31C days, 25C nights, 30.5mm across 5 days and 75 percent humidity.

Barreirinhas-forum threads on an April visit describe this as genuinely near the tail end of the wet season, posters naming December through April as the stretch when lagoons fill toward their fullest. Regulars call early April specifically a real question mark, several posters asking directly about water levels this early before the classic photos are guaranteed. Posters call the water cycle genuinely variable year to year, several regulars naming some years where rain arrives earlier or heavier as the reason timing isn't perfectly predictable. Regulars call real heavy rain a standard April feature regardless of lagoon levels, several threads recommending flexible plans around daily downpours. Posters recommend checking recent conditions with a local operator, several regulars calling this standard given how much lagoons vary week to week. The record: 29.3C days, 24.7C nights, an extraordinarily high 313.8mm across nearly 27 days and 87 percent humidity.

Barreirinhas-forum threads on a mid-March visit describe the lagoons as genuinely refilling well by this point, posters naming March as workable even though June through September remains the classic window for full lagoons. Regulars call three nights in Barreirinhas a real standard base, several posters naming this enough for two full days touring the park's nearest areas. Posters call the Lagoa do Peixes and Lagoa Azul sunset tour a real highlight, several regulars naming the roughly eight to ten hour round trip as the standard way to see both. Regulars call a four-by-four and local guide genuinely necessary from Barreirinhas, several threads naming this the only real way into the dunes and lagoons. Posters recommend booking accommodation in Barreirinhas over other gateway towns, several regulars calling this standard given how central it is to the park. The record: 28.8C days, 24.4C nights, an extraordinarily high 350mm across over 30 days and 87 percent humidity.

Barreirinhas-forum threads on a February visit describe this as genuinely within the wetter stretch of the year, posters naming January-May the real rainy season regardless of exact February dates. Regulars call the lagoon situation genuinely unpredictable, several posters reporting some years bring real full lagoons by February while others describe them still largely dried up. Posters call almost no other tourists a real advantage of February, several regulars describing small lakes between dunes as genuinely filled with water when the rains cooperate. Regulars call daily showers a real feature to expect, several threads warning visitors should plan on getting fully drenched most days despite otherwise warm conditions. Posters recommend March instead for more reliably full lagoons, several regulars calling this the tradeoff against February's real quiet, lower prices. The record: 29C days, 24.6C nights, an extraordinarily high 262.4mm across nearly 26 days and 86 percent humidity.