First Frost & Freeze Dates for Berwyn Heights/College Park/Greenbelt

9/17/2025 Original Post: Predicting first frost or freeze dates is like predicting next months weather -- Good luck with that.  What we have are estimates based on historical data.  In another blog post I discussed the last frost or freeze dates.  Well, the same reasoning applies to this estimate of the first frost or freeze dates.  These dates are published by the National Gardening Association for the College Park ZIP Code 20740.

Temperature	10%	20%	30%	40%	50%	60%	70%	80%	90%
First 16°	1-Dec	7-Dec	11-Dec	14-Dec	18-Dec	21-Dec	24-Dec	29-Dec	3-Jan
First 20°	17-Nov	24-Nov	29-Nov	3-Dec	7-Dec	11-Dec	16-Dec	21-Dec	28-Dec
First 24°	2-Nov	7-Nov	11-Nov	15-Nov	18-Nov	21-Nov	25-Nov	29-Nov	4-Dec
First 28°	16-Oct	21-Oct	24-Oct	28-Oct	30-Oct	2-Nov	5-Nov	9-Nov	14-Nov
First 32°	9-Oct	13-Oct	17-Oct	19-Oct	22-Oct	25-Oct	27-Oct	31-Oct	4-Nov
First 36°	30-Sep	4-Oct	7-Oct	10-Oct	12-Oct	15-Oct	17-Oct	20-Oct	25-Oct

So, on average the 50/50 chance of first frost (36 degree temperature) occurs on October 12 and the 90% chance of frost occurs on October 25.  Can you get your remaining vegetables harvested before the first frost or freeze.  Covering your plants overnight with frost blanket or old sheet can buy you a degree or two of protection.  Instead of frost fabric, I use inexpensive twin-sized fleece blankets that I bought expressly to protect plants from frost and freezing.

11/07/2025 Update:  The weather station I have in the main growing area recorded our first possible frost low temperature of 35 degrees at 6 AM on November 5th, but no frost was seen.  Our first overnight freeze of 31 degrees occurred at 5 AM on November 7th, so it appears that our frost/freeze temperatures are running late this year.