Climate Comfort Score
47/100
Moderate
30-year climate normals from 2 weather stations (1991-2020).
Arco, Idaho has an average annual temperature of 43°F and a climate comfort score of 47/100 (Moderate). Annual precipitation totals 15.5". Based on NOAA 30-year normals (1991–2020).
Avg Temperature
43°F (6°C)
Avg High
53°F
Avg Low
33°F
Annual Precip
15.5"
Comfort Score
47/100
Moderate
Climate Comfort Score
47/100
Moderate
Avg Annual Temperature
43°F
30-year mean (NOAA NCEI)
Annual Precipitation
15.5"
Liquid-equivalent total
PlainClimate composite — temperature mildness, humidity, precipitation, extreme-weather frequency. Moderate for the Arco area.
How the U.S. land temperature anomaly tracks against the global mean since 1900. The current NOAA 1991-2020 normal for Arco captures average conditions across the spread shown — the most recent decade is warmer than the 30-year mean.
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 27°F (-3°C) | 13°F (-11°C) | 20°F (-7°C) | 2.4" | N/A | 31.0 | 0.0 |
| February | 30°F (-1°C) | 15°F (-9°C) | 22°F (-5°C) | 1.2" | N/A | 27.7 | 0.0 |
| March | 40°F (4°C) | 23°F (-5°C) | 32°F (0°C) | 1.9" | N/A | 26.6 | 0.0 |
| April | 51°F (11°C) | 31°F (-1°C) | 41°F (5°C) | 1.1" | N/A | 17.8 | 0.0 |
| May | 62°F (17°C) | 40°F (4°C) | 51°F (11°C) | 1.6" | N/A | 5.8 | 0.0 |
| June | 72°F (22°C) | 46°F (8°C) | 59°F (15°C) | 1.2" | N/A | 0.9 | 0.8 |
| July | 83°F (29°C) | 56°F (13°C) | 70°F (21°C) | 0.3" | N/A | 0.0 | 8.1 |
| August | 82°F (28°C) | 54°F (12°C) | 68°F (20°C) | 0.5" | N/A | 0.0 | 3.8 |
| September | 71°F (22°C) | 45°F (7°C) | 58°F (15°C) | 0.7" | N/A | 1.1 | 0.2 |
| October | 56°F (13°C) | 34°F (1°C) | 45°F (7°C) | 1.2" | N/A | 13.5 | 0.0 |
| November | 39°F (4°C) | 22°F (-6°C) | 31°F (-1°C) | 1.2" | N/A | 26.2 | 0.0 |
| December | 27°F (-3°C) | 14°F (-10°C) | 20°F (-6°C) | 2.0" | N/A | 30.7 | 0.0 |
Average monthly rainfall and snowfall
11.1 days with precipitation
8.2 days with precipitation
11.3 days with precipitation
9.6 days with precipitation
11.3 days with precipitation
7.3 days with precipitation
2.9 days with precipitation
3.7 days with precipitation
4.7 days with precipitation
6.6 days with precipitation
9.2 days with precipitation
11.9 days with precipitation
First Fall Freeze
October 1
50% probability date
Last Spring Freeze
May 24
50% probability date
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
8,331
Higher = more heating needed
Cooling Degree Days
357
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
The NOAA 1991–2020 climate normals describe Arco, Idaho as a location with an annual average temperature of 43°F, ranging from a mean daily high of 53°F to a mean daily low of 33°F. July is typically the warmest month of the year, while January is the coldest. These thirty-year averages, computed from 2 weather stations, smooth out year-to-year variability and give a baseline expectation for typical conditions in any given month.
Precipitation patterns matter as much as temperature for anyone planning to live, garden, or travel here. Arco receives roughly 15.5 inches of precipitation each year, with seasonal snowfall possible. Growing-season length varies with elevation and microclimate, with the last spring freeze near May 24 and the first fall freeze near October 1. For energy use, 8,331 heating degree days and 357 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, Arco scores 47/100 (Moderate), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Use the monthly tables above to plan around specific windows — shoulder seasons for mild highs and lows, peak summer for July-driven heat, or deep winter for January-driven cold. All figures here are thirty-year averages: any single year may run warmer, wetter, drier, or cooler than the normal, so treat them as planning guidance rather than forecasts.
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USW00004126. For informational purposes only.
Read our methodology — how this data is sourced, computed, and verified.