When the rain arrives in Jakarta, and you want to judge how bad it's gonna get, one trick: look at the shoes of the jagas (the guards for parking lots, private houses, office buildings, you name it, everybody has one). If they've changed their boots for flip flops, be careful. It means business. Because there is one thing you need to know: when rain sounds like that, it is futile to try to fight against the mightiness of the monsoon. You'll be wet alright, might as well save your shoes.
Another example. See this nice scene of a bunch of happy young people playing volleyball on the beach? On the right side, it's the same beach with a little bit of a cloud in the distance (sorry, the picture is pretty bad but you might still have an idea of what I'm talking about). Well, when you see this, just know that if you're more than 50 meters from the nearest shelter, start running, otherwise you're going to be soaked. That's fast, man.
Mind you, there are some good thing about tropical downpours. First, it nurtures life. Lots, and lots of life. Second, you don't have to fill up your fish pond; it does it for you. Third, it cools down the air a little bit. Fourth, it provides some money for Jakarta's umbrella boys: when the rain starts, hundreds of colorfull umbrellas pop up out of nowhere, held up high by very small boys who earn a thousand rupiah or two to walk the rich people from the entrance of the mall to their cars. It's easy to recognize a good umbrella boy: he's soaked to the bone, because his job is to protect the rich lady's new perm from being disturbed by a drop of rain.
Come to think of it, I'm not sure we can really count this slave job of poor boys as a good side-effect of the rainy season...
Let's not fool ourselves: the rains are mostly an inconvenience. I will not even dwell on the most dreadful consequence of all, which is the proliferation of mosquitoes and the diseases they spread, particularly in poor neighborhoods (malaria, dengue fever...). Let's just focus on what might interest my readership: rich people stuff.
When you see rain coming (I mean, when you see dark clouds in the distance, because if you've already felt the first drop, it's over), try getting in a cab as fast as possible if you need one within the next hour. Last time, it started raining at 5 PM, right during rush hour, so when I called a taxi at 7 PM to go home I was very glad to hear the operator tell me I was number 98 on the waiting list (even though, despite what your evil - albeit often quite accurate - presuppositions might tell you, the taxi service in Jakarta is pretty good). And that's not the only drawback: it also brings the infamous traffic jams in Jakarta to new heights of horror when the streets get flooded within an hour.
Some find it fun, though.
Finally, here is an ad from the cigarette company Sampoerna. I've already posted another one; I like them because they do reflect some funny cultural aspects of the country. Here, you don't need to understand the dialogue, it's just a bunch of guys ready to go out (you notice it is something important because they all wear new shoes and nice batik shirts)... when the rain strikes.