Do you need to know, when is the best time to go to Guatemala? Then you should take a look here, what weather you can expect there during the year.
The climate of Guatemala is tropical. You can expect hot and humid weather in lowlands, and cooler weather in highlands. The weather may be very cold in the the Cuchumatanes mountains.
When speaking about the usual weather in this state, the information is relevant for example for these popular places: Aguateca, Almolonga, Antigua Guatemala, Cancuén, Cantel, Caribbean Coast, Carmelita, Ceibal, Central Highlands, Chichicastenango, Chiquimula, Cobán, Dolores, Dos Pilas, Eastern Guatemala, El Ceibo, El Mirador, El Naranjo, El Remate, Escuintla, Flores, Guatemala City, Huehuetenango, Ixil Triangle, Iximche, Jaibalito, Jutiapa, Lake Atitlán, Lanquín, Mazatenango, Melchor de Mencos, Mixco Viejo, Monterrico, Nakbé, Nakúm, Northern Lowlands, Pacaya Volcano, Pacific Lowlands, Panajachel, Piedras Negras, Puerto San José, Quetzaltenango, Raxruja, Retalhuleu, Sacapulas, Salcajá, San Andrés, San Andrés Xecul, San Antonio Palopo, San José, San Juan, San Marcos La Laguna, San Miguel, San Pedro la Laguna, San Rafael Pie de la Cuesta, Santa Catarina Palopo, Santa Cruz la Laguna, Santa Lucía Cotzumalguapa, Santa Maria Nebaj, Santiago Atitlán, Sayaxché, Semuc Champey, Solola, Tikal, Todos Santos Cuchumatán, Uaxactun, Uspantan, Western Highlands, Zunil.
Let's look now what weather you can expect in the area around the capital and in many other cities. The warmest month here is April, the average maximum temperature is 27.7 ℃ (81.86 ℉). The average minimum temperature in this month is 16 ℃ (60.8 ℉). The coldest month here is November, the average maximum temperature is 23.5 ℃ (74.3 ℉). The average minimum temperature in this month is 14.4 ℃ (57.92 ℉). The most rainy month here is June, the average number of rainy days is 21.5. The least rainy month here is January, the average number of rainy days is 2. 
When travelling to some places in Guatemala, always consider the altitude of the the place as well. The highest point here is Volcan Tajumulco (4220 m) and the lowest point is Pacific Ocean (0 m). So there are huge differences in altitudes in this country and the weather is very different in them therefore. Keep in mind, that the temperature usually decreases by 1.2 - 1.9 ℃ (2.2 - 3.5 ℉) per 200 m (656 ft), depending on the other conditions. (And we should add, that in the very special condition named thermal inversion even the temperature may be higher in higher altitudes.)
Typical (usual) weather in Guatemala in January is this: The average highest temperature in Guatemala in January is 23.7 ℃ (74.66 ℉). The average lowest temperature is 11.5 ℃ (52.7 ℉). At the beginning of January you can expect lower temperatures, the average highest temperature is around 23.7 ℃ (74.66 ℉). At the end of January you can expect higher temperatures, the average highest temperature is around 24.55 ℃ (76.19 ℉). The average number of rainy days in January is 2. The average rainfall is 3.1 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:16 (hours and minutes), in the middle of the month 11:21 and at the end of the month 11:29.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in February is this: The average highest temperature in Guatemala in February is 25.4 ℃ (77.72 ℉). The average lowest temperature is 13.4 ℃ (56.12 ℉). At the beginning of February you can expect lower temperatures, the average highest temperature is around 24.55 ℃ (76.19 ℉). At the end of February you can expect higher temperatures, the average highest temperature is around 26.1 ℃ (78.98 ℉). The average number of rainy days in February is 2. The average rainfall is 5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:29 (hours and minutes), in the middle of the month 11:39 and at the end of the month 11:51.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in March is this: The average highest temperature in Guatemala in March is 26.8 ℃ (80.24 ℉). The average lowest temperature is 14.1 ℃ (57.38 ℉). At the beginning of March you can expect lower temperatures, the average highest temperature is around 26.1 ℃ (78.98 ℉). At the end of March you can expect higher temperatures, the average highest temperature is around 27.25 ℃ (81.05 ℉). The average number of rainy days in March is 2. The average rainfall is 6.8 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:51 (hours and minutes), in the middle of the month 12:03 and at the end of the month 12:15.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in April is this: The average highest temperature in Guatemala in April is 27.7 ℃ (81.86 ℉). The average lowest temperature is 16 ℃ (60.8 ℉). At the beginning of April you can expect lower temperatures, the average highest temperature is around 27.25 ℃ (81.05 ℉). At the end of April you can expect lower temperatures, the average highest temperature is around 27.4 ℃ (81.32 ℉). The average number of rainy days in April is 5. The average rainfall is 25.9 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:15 (hours and minutes), in the middle of the month 12:27 and at the end of the month 12:38.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in May is this: The average highest temperature in Guatemala in May is 27.1 ℃ (80.78 ℉). The average lowest temperature is 16.5 ℃ (61.7 ℉). At the beginning of May you can expect higher temperatures, the average highest temperature is around 27.4 ℃ (81.32 ℉). At the end of May you can expect lower temperatures, the average highest temperature is around 26.2 ℃ (79.16 ℉). The average number of rainy days in May is 11.1. The average rainfall is 114.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:38 (hours and minutes), in the middle of the month 12:48 and at the end of the month 12:55.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in June is this: The average highest temperature in Guatemala in June is 25.3 ℃ (77.54 ℉). The average lowest temperature is 16.7 ℃ (62.06 ℉). At the beginning of June you can expect higher temperatures, the average highest temperature is around 26.2 ℃ (79.16 ℉). At the end of June you can expect lower temperatures, the average highest temperature is around 24.85 ℃ (76.73 ℉). The average number of rainy days in June is 21.5. The average rainfall is 255.2 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:55 (hours and minutes), in the middle of the month 12:59 and at the end of the month 12:58.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in July is this: The average highest temperature in Guatemala in July is 24.4 ℃ (75.92 ℉). The average lowest temperature is 16.4 ℃ (61.52 ℉). At the beginning of July you can expect higher temperatures, the average highest temperature is around 24.85 ℃ (76.73 ℉). At the end of July you can expect higher temperatures, the average highest temperature is around 24.55 ℃ (76.19 ℉). The average number of rainy days in July is 17. The average rainfall is 182 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:58 (hours and minutes), in the middle of the month 12:55 and at the end of the month 12:47.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in August is this: The average highest temperature in Guatemala in August is 24.7 ℃ (76.46 ℉). The average lowest temperature is 16.4 ℃ (61.52 ℉). At the beginning of August you can expect lower temperatures, the average highest temperature is around 24.55 ℃ (76.19 ℉). At the end of August you can expect lower temperatures, the average highest temperature is around 24.6 ℃ (76.28 ℉). The average number of rainy days in August is 19. The average rainfall is 178.6 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:47 (hours and minutes), in the middle of the month 12:38 and at the end of the month 12:27.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in September is this: The average highest temperature in Guatemala in September is 24.5 ℃ (76.1 ℉). The average lowest temperature is 16.1 ℃ (60.98 ℉). At the beginning of September you can expect higher temperatures, the average highest temperature is around 24.6 ℃ (76.28 ℉). At the end of September you can expect lower temperatures, the average highest temperature is around 24.1 ℃ (75.38 ℉). The average number of rainy days in September is 20.2. The average rainfall is 235 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:27 (hours and minutes), in the middle of the month 12:15 and at the end of the month 12:03.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in October is this: The average highest temperature in Guatemala in October is 23.7 ℃ (74.66 ℉). The average lowest temperature is 15.4 ℃ (59.72 ℉). At the beginning of October you can expect higher temperatures, the average highest temperature is around 24.1 ℃ (75.38 ℉). At the end of October you can expect lower temperatures, the average highest temperature is around 23.6 ℃ (74.48 ℉). The average number of rainy days in October is 14.1. The average rainfall is 133.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:03 (hours and minutes), in the middle of the month 11:51 and at the end of the month 11:39.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in November is this: The average highest temperature in Guatemala in November is 23.5 ℃ (74.3 ℉). The average lowest temperature is 14.4 ℃ (57.92 ℉). At the beginning of November you can expect higher temperatures, the average highest temperature is around 23.6 ℃ (74.48 ℉). At the end of November you can expect higher temperatures, the average highest temperature is around 23.6 ℃ (74.48 ℉). The average number of rainy days in November is 6.1. The average rainfall is 43 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:39 (hours and minutes), in the middle of the month 11:29 and at the end of the month 11:21.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Guatemala in December is this: The average highest temperature in Guatemala in December is 23.7 ℃ (74.66 ℉). The average lowest temperature is 13.3 ℃ (55.94 ℉). At the beginning of December you can expect lower temperatures, the average highest temperature is around 23.6 ℃ (74.48 ℉). At the end of December you can expect lower temperatures, the average highest temperature is around 23.7 ℃ (74.66 ℉). The average number of rainy days in December is 3. The average rainfall is 7.4 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 11:21 (hours and minutes), in the middle of the month 11:16 and at the end of the month 11:15.These numbers above are valid primarily for the capital and the area around it. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.