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Heavy Rainfall for Portions of Coastal Texas; Fire Weather Concerns for Alaska

A tropical disturbance off the Texas coast will bring the threat for some heavy rainfall through Friday. Meanwhile, monsoonal moisture flows into the Southwest and southern Rockies where flash flood threat will increase. Severe thunderstorms are expected across the Upper Midwest and western Great Lakes today. Dry and warm conditions for interior Alaska as fire weather concerns continue. Read More >

 

Spring Frost/Freeze Decision Support Page

 

Definitions of headlines issued by the National Weather Service in Aberdeen, SD: 

Frost Advisory: Issued when conditions are favorable for temperatures to drop between 33 and 36 degrees Fahrenheit resulting in the possibility of widespread frost near the surface. Unprotected vegetation may be damaged. 

Freeze Watch: Issued when conditions are favorable for temperatures to drop below 32 degrees Fahrenheit during the next 12 to 48 hours resulting in the possibility for significant damage to unprotected vegetation.

Freeze Warning: Issued when confidence is high that temperatures will drop below 32 degrees Fahrenheit within the next 24 hours resulting in significant damage to unprotected vegetation.

 

________________________________FORECASTS___________________________________

Click on the Images below for the latest forecast temperature information  

DAY 1 minimum temp forecast

DAY 2 minimum temp forecast

DAY 3 minimum temp forecast

DAY 4 minimum temp forecast

DAY 5 minimum temp forecast

DAY 6 minimum temp forecast

6-10 Day Temp Outlook

8-14 Day Temp Outlook

 

_______________________________OBSERVATIONS__________________________________

Find information regarding past and current temperature observations below

Map display of current temperatures across the region

Map view of the season's last observed 32°/28° temperature
across South Dakota

Map view of the season's last observed 32°/28° temperature across Minnesota

Map view of the season's last observed 32°/28° temperature
across North Dakota

 

 

Table of daily lows at Aberdeen, Watertown, Pierre, Sisseton and Mobridge

Table of daily lows at numerous additional COOP sites

 

 

 

_______________________________CLIMATOLOGY__________________________________

Find climatology information pertaining to frost/freezes below

Median Date of Last 32° Freeze

Date of Latest Last 32° Freeze

Median Date of Last 28° Freeze

Date of Latest Last 28° Freeze
   

Interactive map of the average

last spring freeze (32° F)

Soil temperature climatology

 

 

 

 

 

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The table below presents statistical data regarding the last spring frost/freeze using 1991-2020 data from several NWS COOP sites. "Area" following a location means there have been multiple stations used for the database (within 5 miles of each other). Below are a few examples on how to read the table, using Aberdeen:

  • Mean: May 9th is the average date when temperatures last drop to 32F (May 1st for 28F)
  • 10th: Only 1 in 10 seasons will have a last 32F freeze on or before April 23rd (April 17th for 28F)
  • 90th: 9 in 10 seasons will have a last 32F freeze on or before May 21st (May 15th for 28F)

 

SOUTH  DAKOTA   Spring Freeze Probabilities

Freeze: 32°

Hard Freeze: 28°

Using 1991-2020 Data

Mean

10th

90th

Mean

10th

90th

Aberdeen

5/9

4/23

5/21

5/1

4/17

5/15

Britton

5/5

4/16

5/20

4/26

4/10

5/13

Clark area

5/7

4/22

5/19

4/26

4/10

5/15

Clear Lake

5/4

4/21

5/17

4/23

4/10

5/4

Columbia 8N

5/7

4/17

5/19

4/28

4/13

5/14

Castlewood 5/11 4/26 5/21 5/2 4/17 5/18

Eureka

5/8

4/19

5/20

5/1

4/17

5/15

Faulkton

5/8

4/22

5/20

4/28

4/15

5/15

Gann Valley area

5/11

4/27

5/21

4/30

4/14

5/14

Gettysburg 5/8 4/22 5/18 4/28 4/15 5/14

Highmore

5/12

4/23

5/26

5/6

4/21

5/22

Ipswich

5/10

4/23

5/24

4/30

4/16

5/15

Kennebec

5/11

4/27

5/24

5/4

4/16

5/19

McIntosh 6SE

5/10

4/27

5/21

4/30

4/16

5/15

McLaughlin

5/12

4/26

5/21

5/4

4/19

5/18

Mellette 4W

5/9

4/22

5/20

4/30

4/12

5/16

Milbank area

5/5

4/24

5/15

4/22

4/12

5/7

Miller 5/6 4/20 5/17 4/21 4/11 5/3

Mobridge area

5/8

4/25

5/19

4/29

4/12

5/15

Murdo

5/7

4/20

5/21

4/23

4/10

5/5

Onida 4NW

5/11

4/23

5/24

5/2

5/16

4/17

Pierre

5/7

4/20

5/19

4/25

4/11

5/12

Pollock

5/10

4/24

5/20

5/1

4/16

5/15

Roscoe

5/8

4/20

5/20

4/28

4/11

5/15

Selby

5/12

4/28

5/24

4/29

4/13

5/12

Sisseton area

5/4

4/17

5/16

4/25

4/12

5/12

Summit

5/16

5/2

5/30

5/5

4/18

5/16

Timber Lake

5/11

4/27

5/21

4/30

4/16

5/15

Victor 4NNE

5/3

4/17

5/15

4/21

4/10

5/3

Watertown

5/7

4/23

5/20

4/27

4/16

5/12

Waubay Nat'l Wildlife Refuge

5/3

4/17

5/16

4/21

4/11

4/29

Webster

5/4

4/16

5/16

4/21

4/10

5/3

 

 

 

MINNESOTA   Spring Freeze Probabilities

Freeze: 32°

Hard Freeze: 28°

Using 1991-2020 Data

Mean

10th

90th

Mean

10th

90th

Artichoke Lake (northeast side)

5/1

4/17

5/14

4/18

4/8

5/2

Wheaton

5/1

4/17

5/13

4/21

4/8

5/4

 

While records go as far back as 1895 in some cases, the tables above use just a 30 year period, from 1991-2020. Why? 30 years is an internationally agreed upon timeframe to define "Climate Normals," as determined by the World Meteorological Organization back in 1935 because 1.) 30 numbers gives a statistically reliable estimate for an average and 2.) Climate changes over time. To compare what happens today to the entire period of record would be misleading - what's normal today is often very different than what was normal 50 or 100 years ago. Therefore a gradual adjustment is needed to provide context on what climate is like today. This is important for many practical purposes, such as regulation of power companies, crop selection and planting times, construction planning, and other disciplines and industries. You can see how much the climate has changed visually since the 1901-1930 period across the country via maps here

Here's a specific local example related to 32F freezes: Watertown's average last spring-time 32F temperature of the season is May 7th using 1991-2020 data, but it's May 22nd using 1901-1930 data. This is a 15 day difference. When combined with a 3 day difference in the average first fall-time 32F temperature, you end up with an 18 day shorter season on average for 32F temperatures in today's climate compared to the climate when readings were first recorded.