Alamo Dam, Arizona climate: Climate normals at a NOAA weather station
Alamo Dam's normal year runs from 31°F December nights to 108°F July afternoons, with 7.8 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 20.6°C, December lows of 0°C, July highs of 42°C, 199 mm of precipitation a year.
- NOAA stationAlamo Dam
- Station IDUSC00020100
- Location34.23°N 113.58°W
- Elevation1,290 ft (393 m)
On October 23, the normal high in Alamo Dam is 87°F and the normal low 48°F, and the chance of measurable rain or snow is 7%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Alamo Dam.
- Jan 66° 32°
- Feb 70° 36°
- Mar 77° 41°
- Apr 85° 48°
- May 94° 57°
- Jun 105° 65°
- Jul 108° 74°
- Aug 107° 73°
- Sep 101° 64°
- Oct 90° 51°
- Nov 76° 40°
- Dec 65° 31°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Alamo Dam each month?
July is the warmest month, with normal highs of 108°F; December the coldest, with normal lows of 31°F. The most precipitation falls in August (1.18 in), the least in June (0.06 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 66°F | 32°F | 48.8°F | 1.03 | 4 | <1 | 9 | 10 h 10 min |
| February | 70°F | 36°F | 52.9°F | 1.13 | 4 | <1 | 4 | 11 h |
| March | 77°F | 41°F | 59.3°F | 0.77 | 3 | 3 | 1 | 11 h 50 min |
| April | 85°F | 48°F | 66.6°F | 0.24 | 2 | 12 | <1 | 13 h |
| May | 94°F | 57°F | 75.7°F | 0.08 | 1 | 24 | <1 | 14 h |
| June | 105°F | 65°F | 84.9°F | 0.06 | <1 | 29 | <1 | 14 h 30 min |
| July | 108°F | 74°F | 90.8°F | 0.82 | 3 | 31 | <1 | 14 h 10 min |
| August | 107°F | 73°F | 89.6°F | 1.18 | 5 | 31 | <1 | 13 h 30 min |
| September | 101°F | 64°F | 82.9°F | 0.74 | 3 | 29 | <1 | 12 h 30 min |
| October | 90°F | 51°F | 70.5°F | 0.55 | 2 | 18 | <1 | 11 h 20 min |
| November | 76°F | 40°F | 57.7°F | 0.56 | 2 | 2 | 2 | 10 h 20 min |
| December | 65°F | 31°F | 48.0°F | 0.66 | 3 | <1 | 12 | 9 h 50 min |
| Year (annual) | 87°F | 51°F | 69.0°F | 7.82 | 31 | 179 | 28 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 19°C | 0°C | 9.3°C | 26 mm |
| February | 21°C | 2°C | 11.6°C | 29 mm |
| March | 25°C | 5°C | 15.2°C | 20 mm |
| April | 29°C | 9°C | 19.2°C | 6 mm |
| May | 35°C | 14°C | 24.3°C | 2 mm |
| June | 40°C | 18°C | 29.4°C | 2 mm |
| July | 42°C | 23°C | 32.7°C | 21 mm |
| August | 42°C | 23°C | 32.0°C | 30 mm |
| September | 39°C | 18°C | 28.3°C | 19 mm |
| October | 32°C | 11°C | 21.4°C | 14 mm |
| November | 24°C | 4°C | 14.3°C | 14 mm |
| December | 18°C | 0°C | 8.9°C | 17 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00020100; 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.
Which months are mildest at Alamo Dam?
Normal highs sit between 65°F and 85°F in January, February, March, April and November. Of those, April has the fewest days with rain (2).
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 USC00020100.
When is the last frost at Alamo Dam?
In Alamo Dam, the last spring frost (32°F) comes after March 4 in half of years and after March 31 in one year in ten; the first autumn frost comes before November 23 in half of years and before November 10 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
- March 41 year in 10 after March 31; 9 in 10 after February 13
- First autumn frost, half of years before
- November 231 year in 10 before November 10; 9 in 10 before December 4
NOAA puts the median frost-free season at 261 days, and the season without a hard freeze (28°F) at 294 days.
A hard freeze (28°F) comes after February 13 in half of springs and before December 3 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Alamo Dam in zone 9a in ZIP code 85357, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 9a: the coldest night of a typical year reaches 24°F (17 complete years).
Frost dates for every NOAA station in Arizona · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00020100; 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 at Alamo Dam?
In a normal year in Alamo Dam, 179 days a year reach 90°F (122 of them 100°F or more), 28 nights fall to 32°F or colder and 31 days bring measurable precipitation.
- Days at 90°F or more
- 179a normal year
- Days at 100°F or more
- 122a normal year
- Nights at 32°F or colder
- 28a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 31a normal year
The highest temperature in this station's record (since 1975) is 124°F, on July 29, 1995; the lowest is 19°F, on January 5, 2019.
The wettest calendar year on that record is 1978, with 15.93 in; the snowiest season is 1984–85, with 2.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00020100; records: ACIS (NOAA Regional Climate Centers), station USC00020100. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Alamo Dam?
Over a year 91% of the sunlight that would reach the ground under clear skies gets through the clouds at Alamo Dam, 5.8 kWh per square metre a day. June is the sunniest month (97%) and December the cloudiest (84%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 85% | 3.3 |
| February | 85% | 4.3 |
| March | 89% | 5.8 |
| April | 92% | 7.2 |
| May | 94% | 8.1 |
| June | 97% | 8.6 |
| July | 90% | 7.5 |
| August | 91% | 7.0 |
| September | 93% | 6.2 |
| October | 92% | 4.9 |
| November | 90% | 3.7 |
| December | 84% | 2.9 |
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 many heating and cooling degree days does Alamo Dam record?
A normal year at Alamo Dam brings 1,902 heating degree days, 65% fewer than the median U.S. place (5,373), and 3,378 cooling degree days, 3.7 times the median (908). Three months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 7,189 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 504 | 0 |
| February | 340 | 0 |
| March | 196 | 20 |
| April | 61 | 111 |
| May | 10 | 341 |
| June | 1 | 597 |
| July | 0 | 800 |
| August | 0 | 764 |
| September | 0 | 536 |
| October | 26 | 195 |
| November | 235 | 14 |
| December | 529 | 0 |
| Year (annual) | 1,902 | 3,378 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00020100. 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.
How does Alamo Dam's climate compare?
Alamo Dam is warmer than 64 of the 97 places with their own NOAA record in Arizona, and wetter than 20. Across the 7,247 U.S. stations with normals, its annual mean of 69.0°F is warmer than 94%.
In the Köppen classification computed from these normals, Alamo Dam is BWh: hot desert. 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 Alamo Dam share this climate record?
Alamo Lake has no NOAA station with 1991-2020 normals of its 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.
- Alamo Lake, AZ3 people · 5 mi NE
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 Alamo Dam's climate
What is the coldest month at Alamo Dam?
December, with a normal high of 65°F and a normal low of 31°F. The warmest is July (108°F by day, 74°F at night).
Does it snow at Alamo Dam?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month at Alamo Dam?
August, with 1.18 in of precipitation in a normal year; the driest is June with 0.06 in.
What plant hardiness zone is Alamo Dam in?
The USDA's 2023 map puts Alamo Dam in zone 9a in ZIP code 85357, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 24°F (17 years, 1991-2020): zone 9a.
How late can frost come at Alamo Dam?
In half of years the last 32°F night comes after March 4; in one year in ten it comes after March 31. Waiting until March 31 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Arizona climateThe statewide normals and every place in the state
- Aguila, AZ30 miles from this station, 65.7°F a year
- Bouse, AZ32 miles from this station, 71.3°F a year
- Wikieup, AZ33 miles from this station, 67.1°F a year
- Parker Resrvoir, CA34 miles from this station, 74.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made