Frost dates / Minnesota / Rochester

Frost dates in Rochester, MN

The station on this page is ROCHESTER INTL AP, MN US (USW00014925), 7.6 miles from the city point. Population in the Census 2024 estimate is 123,624.

Zone 4bUSDA average annual extreme minimum -25°F to -20°F, from ZIP 55903 (2.2 miles from the city point used on this page).

Median last 32°F is April 30. Median first 32°F is October 6. The 50% growing-season length is 159 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

Probability	Date	How to read it
90%	April 15	Earlier date. A last 32°F on or after this day is common.
50%	April 30	Median.
10%	May 13	Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

Probability	Date	How to read it
10%	September 22	Earlier date. A first 32°F on or before this day is uncommon.
50%	October 6	Median.
90%	October 20	Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this long	Days
10%	178
50%	159
90%	140

28°F threshold

	10%	50%	90%
Last, on or after	May 2	April 18	April 4
First, on or before	October 4	October 17	October 31
Season at least	201 days	180 days	161 days

36°F threshold

	10%	50%	90%
Last, on or after	May 21	May 9	April 28
First, on or before	September 14	September 28	October 11
Season at least	158 days	140 days	122 days

Station ROCHESTER INTL AP, MN US (USW00014925). Completeness flag S, 30 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 397.5 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

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Rochester, MN

Zone 4bAverage annual extreme minimum -25°F to -20°F

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Minnesota. Nearest qualified station: ROCHESTER INTL AP, MN US (USW00014925), 7.6 miles. Median last 32°F April 30. Median first 32°F October 6. The 50% growing-season length is 159 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	May 13	April 30	April 15
First 32°F on or before	September 22	October 6	October 20

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

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Planting calendar

Frost dates for Minnesota are above. Planting windows appear for states with a cited extension guide. The fall and seed tools use the numbers you enter and the station dates.

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