Last frost date in Magna, UT

Average last frost
April 3

The average last frost in Magna is April 3. By April 19 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about November 4, which leaves 213 frost-free days. An early freeze before October 18 happens one year in ten.

Safe after (10% risk)
Apr 19
Average first frost
Nov 4
Frost-free season
213 days
Hard freeze (28°F) ends
Mar 11
Next 7 nights in Magna

No frost in the next 7 nights

National Weather Service forecast, updated Oct 22, 12:24 UTC

  1. ThuOct 2252°
  2. FriOct 2347°
  3. SatOct 2446°
  4. SunOct 2546°
  5. MonOct 2647°
  6. TueOct 2746°
  7. WedOct 2848°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 3First frost Nov 4213 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND213 frost-free days
Frost risk through the year at Garfield, 2.6 miles from Magna.

Planting calendar for Magna

Windows count forward or back from the average frost dates above. Click a crop for dates across Utah.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesApr 10–Apr 24
PumpkinsApr 17–May 1
SunflowersApr 3–Apr 24
CucumbersApr 17–Apr 24
CornApr 10–Apr 24
Sweet potatoesApr 24–May 8
WatermelonApr 17–May 1
Green beansApr 10–May 1
ZucchiniApr 10–Apr 24
OkraApr 24–May 8
PeppersApr 17–May 1
BasilApr 10–Apr 24
Butternut squashApr 10–Apr 24
CantaloupeApr 17–May 1
EggplantApr 17–May 1
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesMar 6–Mar 20
OnionsFeb 20–Mar 13
CarrotsMar 13–Apr 17
LettuceMar 20–Apr 10
BroccoliMar 6–Mar 20
BeetsMar 6–Apr 17
PeasFeb 20–Mar 6
CabbageMar 6–Mar 20
RadishesFeb 27–Apr 10
Brussels sproutsMar 20–Apr 3
SpinachFeb 20–Mar 13
CilantroMar 20–Apr 10
KaleMar 6–Mar 20
Collard greensMar 6–Mar 20
TurnipsMar 6–Mar 20
DillApr 3–Apr 17
CeleryApr 10–Apr 17
CauliflowerMar 20–Apr 3
LeeksMar 20–Apr 3
Swiss chardMar 20–Apr 17
ParsleyMar 20–Apr 10
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsOct 21–Nov 25
GarlicOct 14–Nov 18
Daffodil bulbsOct 7–Nov 18
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesMar 6–Mar 20
AsparagusMar 6–Mar 20

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FMar 11Apr 3Apr 19Oct 18Nov 4Nov 17
Hard freeze, 28°FFeb 20Mar 11Apr 6Oct 27Nov 13Nov 28

Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.

Where these numbers come from

NOAA station Garfield (USC00423097) sits 2.6 miles from the center of Magna at 4,298 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.

Questions

When is the last frost in Magna, UT?

The average last frost date in Magna is April 3, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 19.

When is the first frost in Magna?

The first frost in fall usually comes around November 4. One year in ten it arrives before October 18.

How long is the growing season in Magna?

About 213 days between the average last and first frost.

When should I plant tomatoes in Magna?

Plant tomato seedlings outside from April 10 to April 24. Start seeds indoors six to eight weeks earlier.

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