The Manabí coast has two seasons, but neither is severe.
December to May is the warm wet season — high humidity, hot days (28–32°C), short heavy downpours in the afternoon. The sea is warmest and the sky is most often blue between rain bursts; this is the local high season for beach travel.
June to November is the cool dry season — air temperatures 22–26°C, the sky often a flat grey from the Humboldt-current marine layer, the sea cooler and choppier. Fewer crowds, lower hotel prices, better for whale-watching: humpbacks migrate up this coast from late June to October and are routinely seen offshore from Puerto López, two hours south.
Carnival (February or early March) is the biggest event of the year, with three days of beach parties and water fights along the Malecón. Hotels book out weeks ahead.