Guatemala City month by month
Figures from Insivumeh for the capital: around 1,275 mm a year, average highs from 23.9 to 27.8 °C and average lows from 13.2 to 16.8 °C. The annual mean is 20.4 °C, and that figure barely moves across twelve months.
01 Fifteen hundred metres of thermostat
The capital sits about 1,500 metres above sea level, and that altitude takes the harshest part out of the tropics. Average highs run from 23.9 °C in December to 27.8 °C in April; average lows from 13.2 to 16.8 °C. The annual mean is 20.4 °C.
Translated into luggage: you will not need winter clothing at any point in the year, but you will want a warm layer for the evenings, especially between December and February, when dawn arrives at thirteen degrees and the city's lowest recorded temperature is 6 °C.
What you feel is radiation, not heat. At this altitude the midday sun is fierce even when the air is cool, and shade drops the sensation by several degrees at once.
02 From 2.8 to 272 millimetres
Here is the real calendar. In January about 2.8 mm fall across the whole month, spread over fewer than two rainy days. In June about 272 mm fall over twenty-one days. That is practically the difference between a desert and a rainforest, in the same place, with nine degrees separating the thermal extremes.
The dry season runs from November to April and is highly reliable: December, January, February and March together add up to less than twenty millimetres. The rainy season runs from May to October and supplies practically all the year's water, some 1,275 mm in total.
Timing matters too. Seasonal rain is an afternoon affair: the morning dawns clear, cloud builds over the mountains and by mid-afternoon it unloads. You can plan a full day if you accept finishing before four.
03 The canícula
The rainy season is not a simple curve but a two-humped one. It climbs to June, dips in July and August, and rises again in September. That mid-season pause is known here as the canícula, and it is a phenomenon recognised by the national weather service.
In the capital's figures the dip is clearly visible: 272 mm in June, 203 in July, 203 in August and 237 in September. It is not a spectacular truce, but it does mean July and August are not the year's worst months, contrary to what people usually assume.
Its length and intensity vary a great deal from year to year and from region to region; in the capital it shows less than in the dry east. Do not count on it when planning, but keep it in mind if your dates fall there and you were writing the summer off.
04 What you see and what you do not
There is an aesthetic reason to prefer the dry season. With clear skies, the line of volcanoes closing the southern horizon is visible from half the city. In the rainy season that view disappears for whole weeks behind the cloud.
The trade-off is that the dry season arrives with a parched landscape and more dust and haze in the air, especially in March and April. November resolves that tension nicely: the rain has stopped, but the valley is still green from the season before.
And a practical note that reaches beyond the city: between June and October landslides and road closures are common in the country's mountainous interior. If the capital is your base for moving around, travel with slack in those months.
Key moments at a glance
Almost no rain, cool nights and visible volcanoes.
The warmest months and the first afternoon storms.
Over 235 mm and twenty-one rainy days in each.
The relative pause inside the wet season.
05 Verdict
Go between November and March. If you can pick one month, pick November: the rain is over, the valley is still green and the air is clean. January and February are the safest bet if what you want is guaranteed sun and you do not mind a drier landscape.
Avoid June and September if you have a choice. And if your dates fall in the wet season, do not cancel: start early, leave afternoons free and expect the city to work exactly the same, only wet from four o'clock on.
