Introduction

I caught the surfing bug during a vacation in Portugal and has been an weekend warrior ever since. In contrast to the warm and pleasant subtropical conditions in Protugal, the Dutch surf scene is quite different: characterized by cold water, wind and rain. As one who surfs only during the weekends, I am truely grateful that my wetsuits allowes surf long sessions without worrying about being cold.

Recently, I decided to invest in some quality wetsuits, to surf all year round. As an engineer who rely on data to make decisions, I started this project analyzing the surf reports on surfweer. Most of the forecasts contain a section on wetsuit recommendations that forms the input of my project.

After web crawling and data cleaning, I was able to gather a number of records for the period from 2019 to 2020. With available information, I would like to get to know:

  • How often is there a "surf day"?
  • What types of wetsuit do I need to surf in different seasons?
a = [2019, 2020]
df = df[df["year"].isin(a)].copy()
df["month"] = df["month"].astype("str")
df["month"] = df["month"].apply(lambda x: month_name(x))

Monthly Surf Days

The collected data contains 239 reports, from January 2019 to February 2021. Before looking into the wetsuits, we will first have a look at the surf condition. From the chart, it is observed that swells are mostly active in early spring and autumn. The frequency dips during the summer months. Note that data was missing for April 2020, due to the pandemic.

Wetsuit Recommendations

According to srface, brands usually advertise their wetsuit neoprene thicknesses as 3/2, 4/3, 5/4, 6/4, etc. 3/2 for instance, means this wetsuit’s main panels are 3mm and 2mm thick. Normally, the chest and back panels are made out of thicker neoprene foam for extra warmth. Arms, shoulders, and legs are usually thinner for more flexibility.

I chose to use the main panel thickness only in the analysis. Wetsuit will be renamed using 3, 4, 5, 6.

Wetsuit

The bar below presents an overview of wetsuit requirement for each month. From the chart, it is shown that either 5mm or 6mm wetsuit is required to surf in the winter months (Nov to Mar). In spring and fall, it requires a combination of 4mm and 5mm wetsuit. A thin wetsuit of 3 mm is suitable for the summer months, especially July and August.

alt.Chart(df).mark_bar().encode(
    y=alt.Y("month:N", axis=alt.Axis(title="month"), sort=month_names),
    x=alt.X("sum(report_count)", axis=alt.Axis(title="counts")),
    color=alt.Color("wetsuit:N"),
).properties()

The chart underneath presents an overview of the number of days that you will need each type of wetsuit throughout the year: 5mm is the mostly often used wetsuit accounting for 40.5 days, which is about 30% of the total surfable days. 3mm wetsuit in the second place, and you could wear it for 33.5 days.

This interactive plot presents the wetsuit recommendation for each month, for each type of the wetsuit. By adjusting the thickness, you could get to know the months and total days that you could surf after purchasing that type of wetsuit.

Which to choose?

Based on the data above, I would like to provide recommendation for three scenarios:

  • Luxury: All of them. With this invested, you are ready for all weather conditoins!
  • Comfort: To maximize the comfort throughout the year, I find it necessary to buy a 5mm and a 3mm wetsuit as the minimum. With these two at hand, you are ready for 80% of surf days, if you subsitue 4mm with either a 5mm or a 3mm on the days when 4mm is recommended.
  • Budget: Let' be realistic, wetsuit is expensive. Considering most of us have day job, we won't wear it that often throughout the year. If the budget is limited, I would recommend purchasing a 4mm wetsuit. With that at hand, you will still be able to surf 50% of the time, if you don't mind being in a 4mm in a tropical day. But it at least made you fully prepared for April, May, September and October which are the months with the best conditions in my opinion.