First call to pytz.timezone is slow in virtualenv

I actually came across the answer by playing around and looking at the source code. Since it gets its timezone settings from within the egg and the first call to timezone has to check that all the timezone files exist, the first call could be slow depending on how the os has to find those files. If pytz is installed using apt-get install python-tz then then call hits uncompressed files and is very fast. If it is installed using easy_install pytz then it hits one compressed file over and over again and is slower.

So the solution is to uncompress it. Luckily pip has a handy command.

tl;dr

pip unzip pytz