The twelve months of the year are always written in lowercase in Spanish and are all masculine, but they are never preceded by the definite article "el"; instead, they are introduced by the preposition "en." Here's an example: En enero nieva.
For a little variety and local knowledge, we've added the typical weather for the 12 months in Spanish for Spain and Latin America as additional information. You'll notice that most Spanish months are spelled very similarly to the English months. Only January differs more significantly in Spanish. We'll start with that month:
January:
Spanish temperatures in January typically range between 5°C and 16°C, with snowfall possible in the mountainous regions. In Latin America, temperatures are pleasant and rain is possible.
February:
It continues to rain in Spain, but temperatures gradually rise. In Latin America, it rains frequently and the weather remains warm.
Marzo | March:
Spring begins in Spain in March, with temperatures between 7°C and 15°C. In Latin America, the climate is warm, especially in tropical regions.
April:
Spring is in full swing in Spain, with pleasant temperatures between 11°C and 21°C. In Latin America, the weather remains warm, and it rains in the tropical regions.
May | May:
Temperatures in Spain in May are warm and sunny, ranging between 14°C and 25°C. In Latin America, the rainy season begins in some areas.
June:
In Spain, it's getting warmer with temperatures between 16°C and 32°C. In Latin America, it rains frequently, and winter begins in the Southern Cone.
July | July:
The heat in Spain increases in July, especially in the interior and the south. In Latin America, the rainy season continues and temperatures drop.
August:
Spain is suffering from extreme heat in many areas. In Latin America, temperatures continue to drop; it is winter in the Southern Cone.
September:
In Spain, the climate remains warm, but temperatures gradually drop to between 19°C and 30°C. In Latin America, rainfall begins to decrease and temperatures rise.
October:
In Spain, autumn begins with temperatures between 14°C and 24°C. Latin America has a hot climate.
November:
The climate in Spain is temperate, with temperatures between 9°C and 18°C and some rainfall. In Latin America, the climate remains warm, with rain in some specific regions.
December:
Winter in Spain is mild, with temperatures between 6°C and 15°C and possible snowfall in the mountainous regions. The climate remains warm in Latin America.