Montevideo climate

Montevideo Frost Dates and Growing Season

NOAA 1991-2020 normals for Montevideo 1SW, 2.7 km from Montevideo, elevation 990 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Montevideo 1SW. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around May 4 and the first fall freeze around October 1, a growing season of about 149 days.

Median at 36°F
last May 12, first September 23
Median at 32°F
last May 4, first October 1
Median at 28°F
last April 26, first October 10

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FMay 27May 22May 19May 15May 12May 10May 8May 5May 1
32°FMay 17May 13May 9May 6May 4May 2Apr 30Apr 27Apr 22
28°FMay 6May 3May 1Apr 28Apr 26Apr 23Apr 20Apr 17Apr 12
24°FApr 30Apr 26Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 3
20°FApr 23Apr 18Apr 13Apr 10Apr 8Apr 6Apr 3Mar 31Mar 24
16°FApr 16Apr 9Apr 6Apr 4Apr 2Mar 31Mar 26Mar 22Mar 15

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 10Sep 15Sep 18Sep 21Sep 23Sep 26Sep 29Oct 2Oct 5
32°FSep 18Sep 22Sep 26Sep 29Oct 1Oct 3Oct 5Oct 9Oct 15
28°FSep 26Oct 1Oct 3Oct 6Oct 10Oct 13Oct 17Oct 20Oct 25
24°FOct 4Oct 10Oct 14Oct 18Oct 22Oct 24Oct 27Oct 31Nov 3
20°FOct 16Oct 22Oct 26Oct 29Oct 31Nov 1Nov 4Nov 8Nov 12
16°FOct 27Oct 31Nov 2Nov 4Nov 7Nov 9Nov 12Nov 15Nov 20

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F149143139134130128123119111
32°F166160156152149146142137130
28°F186179173170167162158154148
24°F208200195190186182177172165
20°F223217211207203200196191184
16°F239233228223219214210205197

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
8,345
Cooling degree days, base 65°F
546
Growing degree days, base 40°F
4,340
Growing degree days, base 45°F
3,352
Growing degree days, base 50°F
2,475
Growing degree days, base 55°F
1,709
Growing degree days, base 60°F
1,062

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,64400
February1,36900
March1,12106
April646147
May27833257
June52121519
July12198651
August29141576
September17549335
October567480
November1,00704
December1,44600

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 2.7 km from Montevideo. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00215563 (Montevideo 1SW). Public domain.