Normal last freeze is April 20-27 period for the area.
Last 36 is typically May 1-7.
Last 40 is in the May 11-18 time frame.
No year is alike & some years have seen very early last freezes or patchy frosts, while other years have been late.
We are forecasting 29-34 for Saturday morning over the area for lows & 32 at Greater Lafayette.
If we officially get to 32 at the Purdue Ag Farm, it would the latest freeze in spring since 2002 when we dropped to 30 on May 21.
We also had 7 days in the 30s for lows after May 8.
We are forecasting 5 this year, making it the most 30s after the 8th since 2002.
The record low for Saturday morning, May 9 is 30 set in 1947 (records back to 1879 & also 1869-70).
The latest freeze on record for Greater Lafayette was 30 on May 27, 1961.
The latest temperature below 28 was 26 on May 10, 1966 with heavy damage to many plant species in near-full foliation.
The latest frost on record was June 22, 1992 when we dropped to 35. The cold, wet summer was the result of the massive 1991 Mount Pinatubo eruption, which was one of the largest eruptions to impact our weather since the Mount Krakatoa eruption in 1883.
However, we did drop to 33 on June 7, 1894 during a significant drought year with large diurnal temperature ranges.
Prior to 1869, patchy frost was reported in June & August 1842 & early June 1859 & very late May 1857 at Greater Lafayette.