Electrum itself is more reliable than this site, i actually checked it during the spike but it still was suggesting 1 Satoshi/byte as transaction fee. possibly some bug in their system.
the link posted above by @TryNinja is also very helpful for estimation of fees. you take a look at mempool size in MB and then figure at which level it reaches 1-1.2 MB and if you pay that much fee you will have a high priority transaction.
for example it currently is 1 but during the spike it was 110 s/b