In fact variables aren't shared across scripts in cron. Even if you define an environment variable like it says in the manpage if you have a script that changes that variable it won't really change for the second script.
However, you can use a temporary file (you can even create it in memory if you don't want to rewrite a file on disk) to use between scripts.
10 * * * * /path/to/script1.sh
20 * * * * /path/to/script2.sh
Contents of script1.sh:
echo "VAR1='VALUE1'" > /dev/shm/cronsharedfile
Contents of script2.sh:
In this case the second script will have the correct value assigned by script1.sh.
I used a file kept in shared memory (/dev/shm/cronsharedfile) but you can create a file on disk (/path/to/whateverfile) .