Map from Google - Swaziland

Swaziland is a small country bordering South Africa and Mozambique, mountainous in the west and hilly in the east, in which the climate varies mainly with altitude. Throughout the country, there is a rainy season from mid-October to mid-April, and a dry season from mid-April to mid-October, but the western area, where the altitude is higher, is rainier than the eastern one. The rains occur primarily as showers or thunderstorms in the afternoon. On the contrary, winter is dry and sunny.
There are three geographical areas which have different climates.
In the west we find the Highveld, crossed by the Drakensberg Mountains, at an altitude between 2,500 and 6,000 feet, where the capital Mbabane is located, has a temperate climate, with cold winter nights, and is covered by forests, rivers and waterfalls. Sometimes during summer it can get hot during the day, but the nights are still cool; sometimes in winter the night temperature can drop below freezing. The rainfall amounts to 40/80 inches per year. The capital Mbabane is situated in this area, at 4,000 feet above sea level.
Here are the average temperatures of Mbabane.
Average temperatures - Mbabane
MbabaneJanFebMarAprMayJunJulAugSepOctNovDec
MbabaneJFMAMJJASOND
Min (°F)595955524641414550525557
Max (°F)777775737066687073737375

In Mbabane, 53 inches of rain per year fall, with a maximum in summer, from November to February, and a minimum in winter, when the rains are rare. Here is the average rainfall.
Average precipitation - Mbabane
MbabaneJanFebMarAprMayJunJulAugSepOctNovDecYear
MbabaneJFMAMJJASONDY
Prec. (in)9.67.75.53.31.40.60.81.22.65.17.57.953.1
Days13111074223610141395

The Midveld lies in the center of the country, between 1,300 and 2,500 feet above sea level, where the second city, Manzini is located. Here the temperature is slightly higher: in winter during the day the weather is nice, it gets cold at night but the risk of frost is lower. On the contrary, in summer it's hot, sometimes very hot, with peaks near 105 °F. The rainfall pattern is the same as that of Mbabane, with a summer maximum and a winter minimum, but the amount is lower, around 35 inches per year.
Here are the average temperatures of Manzini.
Average temperatures - Manzini
ManziniJanFebMarAprMayJunJulAugSepOctNovDec
ManziniJFMAMJJASOND
Min (°F)666664595448485255596164
Max (°F)848281797572737579798182

The Lowveld in the east, between 650 and 1,300 feet, is characterized by a warmer climate and a landscape dominated by the savannah. Rainfall amounts to around 20/35 inches per year. During winter, the nights can be cold, with a wide daily temperature range. Summer is humid and uncomfortably hot.
Average temperatures - Big Bend
Big BendJanFebMarAprMayJunJulAugSepOctNovDec
Big BendJFMAMJJASOND
Min (°F)686866615550505457596466
Max (°F)919088847973757984868890

In the easternmost area, the altitude start to increase slightly again, with the Lebombo Mountains, which despite of their name, do not reach 2,500 feet, so they are more like hills.

Sometimes Swaziland can be affected by tropical cyclones, coming from the Indian Ocean, which lies to the east, beyond the border with Mozambique. The cyclone season in the Southern Hemisphere runs from mid-November to May, but they are most likely from late December to mid-April.

Mlawula Reserve

When to go

The best time to visit Swaziland is from June to September, being the coolest, driest and outside the cyclone season. Being this period in winter, it should be noted, however, that it can get cold at night even in the Lowveld, and even more so in the Highveld, where the temperature can drop below freezing at night from May to August. September is probably the best month, because it's less cold in the mountains.

What to pack

In winter (June to August): for the Highveld and Mbabane, spring/autumn outfit for the day, but also a sweater and jacket for the evening, hiking shoes. For the Midveld, spring/autumn outfit. For the Lowveld, light clothes for the day, jacket and sweater for the evening and the early hours of the morning.

In summer (December to February): for the Highveld and Mbabane, light clothes for the day, sweater and sweatshirt or jacket for the evening, sun hat, umbrella or light raincoat, hiking shoes. For the Midveld, light clothes for the day, light sweatshirt and light jacket for the evening. For the Lowveld, light clothing, light raincoat or umbrella, a light sweatshirt for the evening.