Carry a rain jacket when cycling in Medellin. I learned my lesson shortly after arriving in October.
Medellin is known as 'La Ciudad de la Eterna Primavera' or 'City of Eternal Spring.' The average temperature here of 22C (72F) remains constant throughout the year with only minimal variations (Colombia sits just above the equator). But it can be very wet here. Medellin's tropical rainforest climate averages 224 rain days per year. The months with the highest number of rain days are April and May, as well as September, October, and November (see chart below).
Source: Instituto de Hidrologia Meteorologia y Estudios Ambientales.
However, my Colombian cycling friends tell me that rainfall in the last couple of years has been much higher than normal. They attribute this to El Nino, with Medellin experiencing unusually high rainfall every 4-5 years. In late 2010, dozens of people living on the slopes of Medellin were buried by mudslides.
I couldn't find any data on the Internet measuring the recent rainfall, but I would estimate its currently raining 6 days per week. I had planned a mid-December cycling trip to Letras and La Linea, located approximately 200km south of Medellin. But the rain has been so severe in the last 3 weeks that Letras (a mountain pass) is currently closed. Apparently, the road was washed away in 21 different areas.
I hate riding in the rain, but I hate sitting at home looking out the window too. If there's a break in the weather, I'll go for it. I've only been here a few weeks so its hard to define any weather patterns, but I find that 1) rain showers typically last a couple of hours, and 2) they generally occur in the afternoons. Sometimes I get caught and sometimes I don't. Twice I rode for 2-3 hours in the rain just to get home. And on a couple of other occasions, several dark, dark clouds sat overhead but never opened up.
There is no sense in reading the weather forecast here, as no one has any idea what will happen in the next hour, or the next day. You just have to be prepared. Europe was easier. A particular weather pattern in the Pyrenees, Alps, and Dolomites would last for several days. We would have either constant rain or constant sun. (Although several days of unrelenting rain is worse than Medellin's intermittent rain).
The good news is that the temperatures are always warm. If you get caught in rain on a European mountain pass, the wind-chills can put you into big trouble. Here, you just have to deal with a seriously dirty bike and worn brake-pads.
We are in early December. According to the chart above, the rains should subside at some point this month. Once the road is fixed, I'll be on Letras. And, if you are having doubts about cycling in Medellin because you don't like rain, here is a refresher on Rule Number 5.
Click on the following links for my previous posts on Colombian cycling.
Part I: Colombians and Road Surfaces
Part II: Food and Diet
Part III: Support Vehicles