I'll never forget stepping off the plane in Cape Town in shorts and a T-shirt in mid-July and watching my breath curl upwards. I'd forgotten winter and summer were reversed in the Southern Hemisphere.
My first shopping stop? Long underwear...
It's a sad fact: weather and climate don't come with guarantees, especially when global warming makes temperatures even more unreliable.
Like this day in Istanbul, when I'd planned to take a lot of photographs... and so much fog rolled in I ended up sipping coffee half the day instead.
One recent Easter holiday, British tourists accustomed to cold and rain packed their suntan lotions and bathing suits and headed off to Spain - only to find cold and rain! Had they stayed home, the heat wave in England would have kept them hot and tanned.
So yes, as we know, the weather is impossible to predict. To make your trip (a bit) more predictable I've prepared these little charts to help you decide when to travel, where. But please - if you land down under in winter in your shorts, just don't blame me! (The white squares mean "no opinion" - it's sometimes good, sometimes not, usually an unpredictable mixture).
North America is so vast it's almost impossible to categorize its weather. My favorite season is fall foliage in the northeast US and Quebec. My worst? It's a toss-up between mid-winter in the windswept prairies and high summer in the Southeast US. May can be beautiful anywhere on the West Coast, as can September.
Climate for most of Central America is hot and humid - especially near the coast. To escape the heat, go upwards, into the mountains. The dry season between December and April is the most pleasant travel climate. The rest of the year, brace yourself for heavy rains and tropical storms.
Despite variations, weather throughout the Caribbean is relatively similar. The best time to visit is sometime between November and April, although seasons on some islands are shorter. The rainy season takes up the rest of the time, but of particular note is September-October, the hurricane season. Stay away if you can!
Climate for this region is incredibly diverse and the Equator cuts right across the continent. Depending on which side you're standing, winter and summer are reversed.
In the North, in Colombia and Venezuela, the dry season (and best for visits) is usually winter, sometime between Christmas and Easter. In Ecuador, visit Quito between June and August.
In the Amazon, humidity is just about 100% most of the time with violent storms in the afternoon, usually timed to coincide with the one daily incoming flight.
The best time to travel to the Amazon is June to October. If you're headed to Rio, the June to September summer is pleasant, although the water can be a bit cold.
Along the western coast of the continent, the dry season tends to be around June to October, with the season slightly longer or shorter depending on the country. To visit Macchu Picchu go in winter, between May and mid-September.
Chile, more than 4000km long, has several types of climate, as does Argentina. They range from desert through tropical to nearly Antarctic, or from bikini to parka in a single country.
Climate for most of this region is uniformly torrid, except for the Sahara Desert. The flatter the land the hotter the weather, especially in summer so if you're hot, head up to the highlands, where altitude can make winter downright cold. Coastal areas are greener and wetter - and cooler.
West Africa's climate goes from hot and dry in the Sahel, just South of the Sahara, to hot and humid along the tropical coast. The nearer the coast, the greater the rainfall. Summers are stifling and muggy, winters dryer and cooler. As with most of Africa, avoid the rainy season; rain makes dirt roads muddy and travel difficult, and you'll constantly be swatting mosquitoes.
This is the Africa of the tropics, with majestic rainforests and humidity so thick you could cut it with a knife. In the northernmost part of the region, around the Horn of Africa, the weather is hot, with some areas - such as the below-sea level Danakil Depression in Eritrea - among the hottest on earth.
The region also has some of the highest cities on the planet, with cold nights and cold winters. You might freeze, but you'll take amazing photographs in the crystal clear light of Ethiopian winters.
Don't forget: the further South you go, the colder it gets in winter. April to October, autumn and winter, are usually the best for weather and climate - no rains, warm sunny days, and cool nights. The rains, from November to March, are bearable as long as you are well above sea level. Madagascar, in the Indian Ocean, is a huge island with varied climates - to see the entire island, go in September or October. And if you're there the right day, South Africa will provide you with some of the most spectacular thunderstorms you'll ever see.
Europe's climate tends to be relatively stable - cold in winter, which lasts from around December to February, becoming warmer as summer (July-August) nears. The further North you go the colder it becomes, with the northernmost tips nearly Arctic in winter and the South scorching in summer. Spring can start early and then freeze again. There are distinct rainy seasons in the autumn (October-November) although areas with Atlantic coasts seem to have longer rainy seasons. And even if London tends to be miserable in December, there's a wonderful Christmas spirit in the city so don't let weather alone be your judge!
Central Asia's winters are frigid and snow is frequent, with springtime the best season to visit. South Asia, by contrast, is warmer and more humid, with monsoons for part of the year and cold winters. Climate is also extremely diverse; a country like India ranges from tropical in the South to temperate in the North, near the Himalayas. A trekking holiday could take place either before the monsoons, from February to May, or after them, from October onwards.
This region ranges from temperate Japan in the North to tropical Borneo in the South. Southeast Asia has a tropical climate with plenty of rainfall, except in the more northern mountainous areas, where weather is a bit cooler. The northern part of the continent is more diverse. It can be very cold in Japan in winter - with good skiing too! Weather here is not unlike that of Europe or North America's more temperate regions.
This is the continent that groups Australia, New Zealand, and the islands of the Pacific. Australia and New Zealand are great to visit almost anytime, although Australia's summer (December to February) can be quite hot - but that's what beaches are for! Island weather differs from island to island, although they do share in common tropical wind systems and even cyclones, so check before you go.