Bonn, North Rhine-Westphalia, Germany

Frost dates for Bonn

The full distribution rather than a single date. Every figure below is a percentile of 30 years of daily minimum temperatures at this location, expressed as the date it fell on.

Median last spring frost

21 April

Half of years are later than this. Not a planting date.

Median first autumn frost

6 November

The far end of the outdoor season.

Frost-free season

199 days

Between those two dates in a median year.

Last and first frost by severity

Read a row as: in this fraction of years, the last frost of spring had already happened by this date. The 90% column is the cautious planting date; the 10% column is the gamble.

Light frost — nights at or below 0°C (32°F). Air temperature reaches freezing. Kills basil, beans and unhardened tomatoes; hardy crops shrug it off.
Frost	1 year in 10	Median	9 years in 10	Earliest	Latest
Last of spring	11 Apr	21 Apr	5 May	1 Apr	13 May
First of autumn	14 Oct	6 Nov	19 Nov	9 Oct	26 Nov
Frost-free days	223	199	162	every year on record saw this

Moderate frost — nights at or below -2.2°C (28°F). Damages half-hardy plants and most blossom. This is the threshold that decides a fruit crop.
Frost	1 year in 10	Median	9 years in 10	Earliest	Latest
Last of spring	20 Mar	13 Apr	23 Apr	25 Feb	27 Apr
First of autumn	19 Oct	16 Nov	2 Dec	14 Oct	19 Dec
Frost-free days	257	217	179	every year on record saw this

Hard frost — nights at or below -4.4°C (24.1°F). Ground freezes and even hardy crops check their growth. Effectively the end of the outdoor year.
Frost	1 year in 10	Median	9 years in 10	Earliest	Latest
Last of spring	28 Jan	7 Mar	5 Apr	13 Jan	14 Apr
First of autumn	5 Nov	29 Nov	21 Dec	23 Oct	28 Dec
Frost-free days	327	267	214	every year on record saw this

Dates in the southern hemisphere are computed on a growing year that starts in July, which is why "last of spring" falls where it should rather than in the middle of the calendar.

Chance of frost, week by week

Chance of at least one air frost during each week of the year, measured across the full record. The flat stretch in the middle is your frost-free season.

Temperature through the year

Mean monthly temperature across the record. Months shown in blue average at least one air frost.

Monthly means and average number of frost nights.
Month	Mean low	Mean high	Frost nights
January	-2.3°C	2.7°C	20.3
February	-1.7°C	4.5°C	17.7
March	0.2°C	8.4°C	14.9
April	2.9°C	12.7°C	6.7
May	6.9°C	16.8°C	0.3
June	10.2°C	20.6°C	0
July	12.3°C	22.9°C	0
August	12.3°C	23.2°C	0
September	9°C	19.2°C	0
October	5.7°C	13.7°C	2.2
November	2°C	7.3°C	8.6
December	-1.1°C	3.4°C	18.3

Turn these dates into a planting calendar →

Nearby

Compare with places close by

Köln Zone 8a 24 km Last frost 17 Apr First 10 Nov Wuppertal Zone 8a 58 km Last frost 17 Apr First 11 Nov Düsseldorf Zone 8a 59 km Last frost 17 Apr First 10 Nov Mönchengladbach Zone 8a 68 km Last frost 15 Apr First 11 Nov Aachen Zone 8a 71 km Last frost 15 Apr First 11 Nov Krefeld Zone 8a 77 km Last frost 14 Apr First 11 Nov Essen Zone 8a 81 km Last frost 17 Apr First 11 Nov Duisburg Zone 8a 81 km Last frost 17 Apr First 11 Nov