Has Climate Had An Impact On COVID Growth?

There's been a lot of speculation about how much warmer temperatures might help us in the fight against COVID.  There's reason to believe it could.  The flu is a seasonal virus that grows rapidly in the fall and practically disappears in the spring.  When I started building my COVID Tracking Spreadsheet,  I made sure to select countries from the northern, southern, and equatorial regions so we could compare them.  Because it helps to compare cases on a common timeline where Day 1 for each country is where they have > 100 cases, it has taken a while to get enough data -- most of the equatorial and southern countries only recently joined the > 100 case club.

Now we can take a first look at comparing how countries in different regions did.

Click to Enlarge

To make it easier to compare,  all northern countries are Yellow, equatorial in Green, southern in Purple. The US is in Blue (while technically India is a northern country, I grouped it with the equatorial because of its similar climate for most of its population).So far, the Equatorial countries are on a very different growth path than the northern ones.  There is no northern country with a lower case amount than ANY equatorial country in my group - regardless of population or economy. 

When I first say it, I wondered if its possible the equatorial countries aren't testing as much as the northern countries so they just aren't discovering cases.  Let's look at the number of tests each country had competed by Day 12:

Country	Tests as of Day 12
USA	15,535
Italy	31,000	estimate
S Korea	125,851
France	21,620
UK	50,422
Canada	142,154
India	24,254
Philippines	2,147	as of day 11
Malaysia	14,000
Thailand	14,086
Vietnam	30,548	as of day 4
Australia	52,663

While there are quite a range of testing, the differences don't seem enough to explain the difference in trends.

Warm climate still isn't necessarily the only reason for the slower growth. Most of these countries had several more weeks to prepare for COVID and may have done a better job at testing and isolating early cases.  It's also important to note that these countries aren't acting like COVID won't be a problem for them.  Yesterday India ordered a major shutdown of their economy to hold off the virus (although they are only testing a couple thousand people a day in a country of 1.3 Billion!  Rwanda, another country on the equator has also shut down schools and businesses.  If the warmer climate will tame COVID, their leader's aren't counting on it. 

As the spring progresses, it will become obvious if that is enough to save us from COVID.  For now, its best to keep R0 low by practicing social distancing, self quarantining if you have a fever or cough, and washing your hands often.