It rained a lot when i was in Penang. We had to change plans a few times, ran in and out between shelters and most of my photos turned out grey. Amazingly, i still had a really good time.
If you only have time for one heritage visit when in Penang, i would strongly recommend the Cheong Fatt Tze Mansion (aka The Blue Mansion). Built in 1880s, it went through amazing restoration work in 1990s and won the UNESCO Most Excellent Award for Culture Heritage Conservation in year 2000.
By guided tours only. The lady who brought us around was very professional and humorous. For once i wasn’t daydreaming during talks.