According to one Bitcoin halving date calculation, the fourth halving is likely to happen on Apr., 20. Previous halvings preceded years of significant growth in the cryptocurrency's market price.
A recent post on /r/Bitcoin shared a screenshot of what is purported to be a Bitcoin Halving Date calculator output estimating the next Bitcoin halving will happen on 4/20. That would be especially neat because it will happen on block 840,000, and 420,000 is half of that number.