What if Tokyo 2020 was in 2020?

Chelsea Carlson

Chelsea Carlson, meteorologist for the US Olympic Sailing Team, offers a view of what the Tokyo 2020 Olympics would have been like if they had not been postponed a year from their original dates of July 24 to August 9:

The Tokyo Olympics were arguably one of the biggest of the COVID-19 postponements of the year, so this summer there was plenty of time to pay attention (albeit remotely) to Enoshima, the official sailing venue for the Tokyo Games.

Over the past three summers, we (myself with the US Sailing Team) have watched, experienced, and logged volumes of weather data in an attempt to capture and understand the patterns of the venue. Typically, this is done in-person with sensors aplenty, but obviously this year has been different and all the monitoring was done remotely…thank goodness for technology!

While 2018 and 2019 were each slightly different, they both featured fairly typical summertime conditions for Japan. Enoshima has a history of being a mixed-bag venue when it comes to weather.

A light northerly wind regime (often accompanied by clouds and rain) can last for days followed quickly by sunny days with a stronger southerly to southwesterly wind. Wind strength can vary from the lightest sea breezes to strong gradient winds with large swells, especially if there are typhoons nearby, which is a regular seasonal occurrence.

High heat and humidity are staples, and the heat has made the headlines on more than once occasion over the last few summers.

Around this time (late August) in 2018, Japan saw a heat wave with temperatures that reached a National all-time high of 106 degrees. Then, in late July 2019, they saw another unprecedented heat wave killing nearly 60 people in a week and hospitalizing nearly 18,000. As a result, some running events like the marathon were moved further north to avoid the predicted heat.

The expectation was that that the 2020 Games window would follow suite – but if we’ve learned anything, it’s that 2020 will not go as planned. The majority of July this year actually saw temperatures slightly below normal, with lots of cloudy skies and a sunshine duration only 40% of what’s normal.

Even though it wasn’t unbearably hot, I can’t say that the Olympics would have been all that pleasant if held this year, with lots of drizzly-rain for several days at time and light fluky winds – not the most ideal sailing conditions. Excessive rainfall amounts were recorded – up to +80% more than normal, and the rain was so heavy in places that there were a few major landslides and flooding disasters across inland areas.

Source: Japan Meteorological Agency

There is actually a fairly simple explanation for this turn of events. There is a rainy season in Japan that usually ends sometime in June. The stalled-frontal boundary that causes the rains (called the Baiu-front) occasionally lingers into early July, but this year it took over most of the month, and overlapped into the “Games period” starting the end of July.

Alas, things eventually did change, the rainy season ended, and the typical summertime heat started to come back during the first part of August. And with it, the heat returned. So the tail end of the Olympic period (though August 8th) likely would have been much more typical of summer, hot and sunny, and most importantly – more wind.

As of August 17, Japan tied that 2018 all-time high record of 106 degrees, in yet another heat wave.

Sources:
• http://ds.data.jma.go.jp/tcc/tcc/products/japan/climate/index.php?kikan=mon
• https://www.washingtonpost.com/weather/2020/08/17/japan-high-temperature-record/
• https://english.kyodonews.net/news/2019/08/ad018e01451f-57-dead-18000-taken-to-hospitals-in-week-in-japan-heat-wave.html
• https://www.bbc.com/news/world-asia-44935152

Olympic Sailing Program
Men’s One Person Dinghy – Laser
Women’s One Person Dinghy – Laser Radial
Men’s Two Person Dinghy – 470
Women’s Two Person Dinghy – 470
Men’s Skiff – 49er
Women’s Skiff – 49erFx
Men’s One Person Dinghy Heavy – Finn
Men’s Windsurfing – RS:X
Women’s Windsurfing – RS:X
Mixed Multihull – Nacra 17

Original dates: July 24 to August 9, 2020
Revised dates: July 23 to August 8, 2021

Details: https://tokyo2020.org/en/games/schedule/olympic/