I just compared daily average soil temps (4" deep) for my microclimate via our local weather station. This is very fun stuff and I will use this data to select my planting dates this year.
his time last year, our soil was 46.9°, and the ideal planting dates were around April 28th, when soil temp was around 60°. Today our average soil temp was 52° (or 11% warmer than last year). If degree rise over time is the same as last year, I'll be planting by about April 22nd.
I look at this and think: if I only wanted 50° soil I could plant now, but with snow + rain "snain" in the forecast, I have to come back to reality.