---
title: Rainy seasons on schedule
date: 2026-06-27T20:01:59+08:00
categories:
  - visualization
  - data
---

[Karthik Sashidhar](https://karthiks.co/) shared his [AI-generated Bangalore weather blog](https://weather.karthiks.co/blog/), which is generated by Hermes listening on Telegram. "The data analysis and stuff is still fairly YOLO but ... [skill](https://github.com/skthewimp/karthik-data-visualization-skill/blob/e51dec1af9ec66b053767c84bba5badb808281ae/karthik-data-visualization/claude/SKILL.md) based on my 10 years of experience," as he put it. That includes [critique](https://github.com/skthewimp/karthik-data-visualization-skill/blob/3179c1cf77d47635e230b4720738a5bcea49b267/dataviz-critique/claude/SKILL.md) too.

[Arjun](https://arjun010.github.io/) asked it: Does it rain at specific hours in the day during monsoons?

In a few minutes, [Pre-monsoon rain is an evening creature](https://weather.karthiks.co/blog/pre-monsoon-evening-rain.html) emerged. In short, it rains in the evenings: 5 - 6 pm is the peak.

That got me curious: how reliable is this advice? I mean, if someone told me, "Carry an umbrella if you're going out between 3-7pm", does that advice change month-on-month? How likely am I to get wet despite following it?

[![](https://sanand0.github.io/datastories/rainy-seasons/screenshot.avif)](https://sanand0.github.io/datastories/rainy-seasons/)

It turns out that based on 10 years of [Open-Meteo](https://open-meteo.com/en/docs/historical-weather-api) data, the answer does change a bit based on the season. In July, when it rains the most, 1 - 7 pm is when you should carry an umbrella. There's a 43% risk of rain in this window, but only 18% outside it.

But the city with the clearest advice is Caracas, Venezuala. In August (or almost any month), carry an umbrella between 12 - 6 pm. There's a 57% chance it'll rain then - and only 6% outside.

[![](https://files.s-anand.net/images/2026-06-27-rainy-seasons-on-schedule-caracas.avif)](https://sanand0.github.io/datastories/rainy-seasons/#?city=Caracas)

Or Abidjan, Ivory Coast. In October, carry an umbrella between 11 am - 5 pm. 72% chance of rain, 15% outside.

[![](https://files.s-anand.net/images/2026-06-27-rainy-seasons-on-schedule-abidjan.avif)](https://sanand0.github.io/datastories/rainy-seasons/#?city=Abidjan)

Some cities, like Mumbai, India, are hopeless. In July, _always_ carry an umbrella. 86% chance between 2 - 8 am (when it rains the most), and 80% outside.

[![](https://files.s-anand.net/images/2026-06-27-rainy-seasons-on-schedule-mumbai.avif)](https://sanand0.github.io/datastories/rainy-seasons/#?city=Mumbai)

In some, like Taichung, Taiwan, it depends. Summer rain is predictable. In winter, it might rain at any time.

[![](https://files.s-anand.net/images/2026-06-27-rainy-seasons-on-schedule-taichung.avif)](https://sanand0.github.io/datastories/rainy-seasons/#?city=Taichung)

The opposite is true for Surabaya, Indonesia and Sao Paulo, Brazil.

[![](https://files.s-anand.net/images/2026-06-27-rainy-seasons-on-schedule-surabaya.avif)](https://sanand0.github.io/datastories/rainy-seasons/#?city=Surabaya)

[![](https://files.s-anand.net/images/2026-06-27-rainy-seasons-on-schedule-sao-paulo.avif)](https://sanand0.github.io/datastories/rainy-seasons/#?city=Sao+Paulo)

My father often complains about the peculiar weather in Chennai, India. It doesn't rain too much, but in the rainy seasons. there's no fixed schedule.

[![](https://files.s-anand.net/images/2026-06-27-rainy-seasons-on-schedule-chennai.avif)](https://sanand0.github.io/datastories/rainy-seasons/#?city=Chennai)

Maybe that's part of what makes rain forecasts accurate in some cities - just knowing the season is enough to predict rain timings.