The hope that we are done with very cold temperatures increases each day as April progresses, but the featured map shows the reality that for most of Iowa, a hard freeze (low temperature below 29°F) is still more likely than not. The map presents the percentile that April 15th resides at for having the last such daily cold low temperature of the season. Rewording, a value of 50 indicates that 50 percent of years have seen the final sub 29°F by April 15. So values below 50 indicate that more years than not have seen such a cold temperature after the date. A caveat for the plot as micro-climates at individual stations and local topography can significantly influence this metric, but the chart shows the general signal. Much of the state has a number of weeks to go before such cold temperatures become a rare event.

Voting:
Good = 15
Bad = 3