Being Canadian, weather is the subject of daily conversation. We have such a variety, with four very distinct seasons. Here in Leon and the rest of Nicaragua things do not vary that much, it is hot and dry or hot and wet.
As of today, October 7th, we are deep into the rainy season. This is Nicaragua's "invierno" or winter and it runs from May to November. We have been told that September and October are the rainiest, so far that has been true.
Hot, humid, sunny mornings turn into torrential downpours almost daily. One positive to living closer to the water is the almost daily breezes we get that make for a cooler evening and better sleeping conditions.
The other season is "verano" or summer and it runs from November to April. This is the dry season with the nicest weather being December to February, a good time for hiking and camping. As you go into the late summer, trees start to lose their leaves, vegetation dries up and the temperatures soar to high 30's C and beyond.
The Atlantic coast has a bit different climate in that it is much wetter and rains all year. Although it has a beauty all it's own, go prepared for moisture.
If you want a bit of "cooler" weather there are the central "highland" areas where temperatures may dip to 12C at night and cool cloud forests rest atop the volcanoes. Here is where you will find the coffee plantations, flourishing in the rich volcanic soil.
Point of Interest: Seeing we are still in the northern hemisphere we expected the seasons to be the same. Here in Central America however the seasons are named for their actual conditions not time of year. Therefore: wet=not so nice=winter, dry=nice=summer.