Alexandria, South Dakota climate: Normal weather by month, frost dates and records
Alexandria's normal year runs from 6°F January nights to 84°F July afternoons, with 25.3 inches of precipitation and 36 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.2°C, January lows of −15°C, July highs of 29°C, 643 mm of precipitation a year.
- NOAA stationAlexandria
- Station IDUSC00390128
- Location43.65°N 97.80°W
- Elevation1,365 ft (416 m)
- From the centerunder 1 mile
- Population657
On October 23, the normal high in Alexandria is 56°F and the normal low 31°F, and the chance of measurable rain or snow is 19%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Alexandria.
- Jan 25° 6°
- Feb 31° 10°
- Mar 44° 21°
- Apr 58° 32°
- May 69° 44°
- Jun 79° 56°
- Jul 84° 60°
- Aug 82° 57°
- Sep 75° 49°
- Oct 60° 35°
- Nov 43° 21°
- Dec 29° 10°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Alexandria each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 6°F. The most precipitation falls in June (3.97 in), the least in January (0.47 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 25°F | 6°F | 15.5°F | 0.47 | 6.1 | 5 | <1 | 31 | 9 h 20 min |
| February | 31°F | 10°F | 20.3°F | 0.74 | 8.0 | 5 | <1 | 27 | 10 h 30 min |
| March | 44°F | 21°F | 32.2°F | 1.13 | 5.2 | 6 | <1 | 24 | 11 h 50 min |
| April | 58°F | 32°F | 44.8°F | 2.88 | 4.7 | 8 | <1 | 12 | 13 h 20 min |
| May | 69°F | 44°F | 56.9°F | 3.64 | 0.0 | 11 | 1 | 1 | 14 h 40 min |
| June | 79°F | 56°F | 67.4°F | 3.97 | 0.0 | 10 | 5 | <1 | 15 h 30 min |
| July | 84°F | 60°F | 72.1°F | 3.13 | 0.0 | 8 | 10 | <1 | 15 h 10 min |
| August | 82°F | 57°F | 69.6°F | 3.02 | 0.0 | 7 | 6 | <1 | 14 h |
| September | 75°F | 49°F | 61.9°F | 2.81 | 0.0 | 7 | 3 | <1 | 12 h 30 min |
| October | 60°F | 35°F | 47.4°F | 2.01 | 0.9 | 7 | <1 | 9 | 11 h 10 min |
| November | 43°F | 21°F | 32.3°F | 0.92 | 3.2 | 4 | <1 | 24 | 9 h 40 min |
| December | 29°F | 10°F | 19.7°F | 0.60 | 8.2 | 5 | <1 | 31 | 9 h |
| Year (annual) | 57°F | 33°F | 45.0°F | 25.32 | 36.3 | 81 | 25 | 159 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −4°C | −15°C | −9.2°C | 12 mm | 15 cm |
| February | −1°C | −12°C | −6.5°C | 19 mm | 20 cm |
| March | 7°C | −6°C | 0.1°C | 29 mm | 13 cm |
| April | 14°C | 0°C | 7.1°C | 73 mm | 12 cm |
| May | 21°C | 7°C | 13.8°C | 92 mm | 0 cm |
| June | 26°C | 13°C | 19.7°C | 101 mm | 0 cm |
| July | 29°C | 16°C | 22.3°C | 80 mm | 0 cm |
| August | 28°C | 14°C | 20.9°C | 77 mm | 0 cm |
| September | 24°C | 9°C | 16.6°C | 71 mm | 0 cm |
| October | 16°C | 2°C | 8.6°C | 51 mm | 2 cm |
| November | 6°C | −6°C | 0.2°C | 23 mm | 8 cm |
| December | −2°C | −12°C | −6.8°C | 15 mm | 21 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00390128; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Alexandria?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (7).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00390128.
When is the last frost in Alexandria?
In Alexandria, the last spring frost (32°F) comes after May 8 in half of years and after May 21 in one year in ten; the first autumn frost comes before September 29 in half of years and before September 17 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 81 year in 10 after May 21; 9 in 10 after April 27
- First autumn frost, half of years before
- September 291 year in 10 before September 17; 9 in 10 before October 11
NOAA puts the median frost-free season at 143 days, and the season without a hard freeze (28°F) at 161 days.
A hard freeze (28°F) comes after April 30 in half of springs and before October 7 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Alexandria in zone 5a in ZIP code 57311, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Alexandria's NOAA station is in zone 5a: the coldest night of a typical year reaches −19°F (25 complete years).
Frost dates for every NOAA station in South Dakota · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00390128; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Alexandria?
In a normal year in Alexandria, 25 days a year reach 90°F (1 of them 100°F or more), 159 nights fall to 32°F or colder and 81 days bring measurable precipitation.
- Days at 90°F or more
- 25a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 159a normal year
- Days that stay below freezing
- 60high of 32°F or less
- Days with 0.01 inch of precipitation
- 81a normal year
- Days with 1 inch of snow or more
- 11a normal year
The highest temperature in this station's record (since 1893) is 114°F, on July 17, 1936; the lowest is −41°F, on January 12, 1912.
The wettest calendar year on that record is 2019, with 41.68 in; the snowiest season is 1968–69, with 61.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00390128; records: ACIS (NOAA Regional Climate Centers), station USC00390128. Records use complete months only; a month missing more than three days is left out.
How sunny is Alexandria?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Alexandria, 4.2 kWh per square metre a day. July is the sunniest month (86%) and December the cloudiest (71%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 76% | 2.0 |
| February | 79% | 3.1 |
| March | 71% | 3.9 |
| April | 72% | 5.0 |
| May | 72% | 5.8 |
| June | 79% | 6.5 |
| July | 86% | 6.8 |
| August | 82% | 5.6 |
| September | 80% | 4.5 |
| October | 74% | 3.1 |
| November | 75% | 2.1 |
| December | 71% | 1.6 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Alexandria need?
A normal year in Alexandria brings 7,874 heating degree days, 47% more than the median U.S. place (5,373), and 626 cooling degree days, 31% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,614 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,533 | 0 |
| February | 1,252 | 0 |
| March | 1,016 | 0 |
| April | 610 | 2 |
| May | 279 | 28 |
| June | 53 | 126 |
| July | 12 | 232 |
| August | 26 | 169 |
| September | 159 | 65 |
| October | 552 | 5 |
| November | 981 | 0 |
| December | 1,403 | 0 |
| Year (annual) | 7,874 | 626 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00390128. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Alexandria been warmer than normal lately?
2024 averaged 48.8°F, 3.8°F above the 1991-2020 normal of 45.0°F. 4 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 48.4°F | +3.4°F | 18.45 | 15.1 |
| 2022 | 45.5°F | +0.5°F | 19.01 | 17.7 |
| 2023 | 47.5°F | +2.5°F | 23.66 | 47.0 |
| 2024 | 48.8°F | +3.8°F | 27.68 | 22.3 |
Over 90 complete years from 1883 to 2024, the station's annual mean temperature rose at a fitted 1.9°F per century (+0.11°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00390128; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Alexandria's climate compare?
Alexandria is warmer than 38 of the other 99 places with their own NOAA record in South Dakota, and wetter than 68. Across the 7,247 U.S. stations with normals, its annual mean of 45.0°F is warmer than 19%.
In the Köppen classification computed from these normals, Alexandria is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Alexandria share this climate record?
12 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Ethan, SD358 people · 12 mi SW
- Dimock, SD154 people · 15 mi SW
- Spencer, SD136 people · 12 mi NE
- Fulton, SD84 people · 5 mi N
- Millbrook Colony, SD54 people · 4 mi W
- Old Elm Spring Colony, SD45 people · 11 mi S
- New Elm Spring Colony, SD40 people · 11 mi S
- Oak Lane Colony, SD37 people · 10 mi S
- Rockport Colony, SD25 people · 5 mi SW
- Farmer, SD15 people · 7 mi NE
- Milltown, SD5 people · 16 mi S
- Rosedale Colony, SD0 people · 4 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Alexandria's climate
What is the coldest month in Alexandria?
January, with a normal high of 25°F and a normal low of 6°F. The warmest is July (84°F by day, 60°F at night).
Does it snow in Alexandria?
Yes: 36 inches in a normal year, falling on 18 days with 0.1 inch or more, the most in December (8.2 inches).
What is the rainiest month in Alexandria?
June, with 3.97 in of precipitation in a normal year; the driest is January with 0.47 in.
What plant hardiness zone is Alexandria in?
The USDA's 2023 map puts Alexandria in zone 5a in ZIP code 57311, the nearest ZIP area. By the same method at Alexandria's NOAA station, the coldest night of a typical year reaches −19°F (25 years, 1991-2020): zone 5a.
How late can frost come in Alexandria?
In half of years the last 32°F night comes after May 8; in one year in ten it comes after May 21. Waiting until May 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- South Dakota climateThe statewide normals and every place in the state
- Mitchell, SD14 miles from this station, 47.7°F a year
- Bridgewater, SD16 miles from this station, 46.4°F a year
- Salem, SD25 miles from this station, 44.4°F a year
- Howard, SD28 miles from this station, 46.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made