Climate Comfort Score
34/100
Below Average
NOAA 1991–2020 normals 42°F annual avg Public-domain federal data
May, ID Climate
Annual temperature, rainfall, and a comfort score, sourced from NOAA NCEI's 1991–2020 normals →
- 42°F
- Avg annual temp
- 34/100
- Comfort score
- 8.5"
- Annual precip
- 86d
- Growing season
30-year climate normals from 1 weather station (1991-2020).
The climate verdict for May
May, Idaho averages 42°F a year and scores 34/100 on the comfort index - below average, milder than 1% of U.S. cities.
- 42°F
- annual average temperature (NOAA normal)
- 34/100
- comfort score, milder than 1% of U.S. cities
- 8.5"
- precipitation, annual total
- 86 days
- frost-free days per growing season
Based on NOAA U.S. Climate Normals (1991–2020) - 30-year averages describing the typical year, not a forecast.
Avg Temperature
42°F (6°C)
Avg High
59°F
Avg Low
26°F
Annual Precip
8.5"
Comfort Score
34/100
Below Average
Avg Annual Temperature
42°F
30-year mean (NOAA NCEI)
Annual Precipitation
8.5"
Liquid-equivalent total
Comfort score vs national 100-point ceiling (May) 34.0%
National median (63)
PlainClimate composite, temperature mildness, humidity, precipitation, extreme-weather frequency. Below Average for the May area.
How May compares to every U.S. city
May's comfort score vs. all U.S. cities
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
34 Top 99% higher than 1% of 6,915 US cities
Each bar is a band; taller bars hold more US cities. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Warming context for May
MethodologySince 1900, U.S. land temperatures have tracked (and diverged from) the global mean - the chart below shows how. May's current NOAA 1991-2020 normal sits within that longer spread, and the most recent decade runs warmer than the 30-year mean.
- United States land mean (NOAA NCEI) +0.11 °C/decade
- Global anomaly (NASA GISTEMP) +0.11 °C/decade
- Paris Agreement thresholds 1.5°C / 2.0°C
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 32°F (0°C) | 6°F (-14°C) | 19°F (-7°C) | 0.3" | 30.9 | 0.0 |
| February | 39°F (4°C) | 13°F (-11°C) | 26°F (-3°C) | 0.3" | 27.8 | 0.0 |
| March | 51°F (10°C) | 19°F (-7°C) | 35°F (2°C) | 0.7" | 29.1 | 0.0 |
| April | 58°F (15°C) | 25°F (-4°C) | 42°F (5°C) | 0.8" | 25.8 | 0.0 |
| May | 68°F (20°C) | 34°F (1°C) | 51°F (10°C) | 1.2" | 11.8 | 0.1 |
| June | 76°F (24°C) | 41°F (5°C) | 58°F (15°C) | 1.3" | 1.6 | 2.3 |
| July | 87°F (30°C) | 45°F (7°C) | 66°F (19°C) | 0.5" | 0.0 | 14.1 |
| August | 85°F (30°C) | 42°F (6°C) | 64°F (18°C) | 0.9" | 0.3 | 7.9 |
| September | 76°F (24°C) | 35°F (2°C) | 56°F (13°C) | 0.9" | 8.9 | 0.7 |
| October | 60°F (16°C) | 25°F (-4°C) | 43°F (6°C) | 0.9" | 24.0 | 0.0 |
| November | 44°F (6°C) | 17°F (-9°C) | 30°F (-1°C) | 0.5" | 29.3 | 0.0 |
| December | 32°F (0°C) | 9°F (-13°C) | 21°F (-6°C) | 0.3" | 30.7 | 0.0 |
Monthly Precipitation
Average monthly rainfall
January 0.3"
3.1 days with precipitation
February 0.3"
2.9 days with precipitation
March 0.7"
4.2 days with precipitation
April 0.8"
5.3 days with precipitation
May 1.2"
7.1 days with precipitation
June 1.3"
6.8 days with precipitation
July 0.5"
3.6 days with precipitation
August 0.9"
4.8 days with precipitation
September 0.9"
4.4 days with precipitation
October 0.9"
5.4 days with precipitation
November 0.5"
4.2 days with precipitation
December 0.3"
3.3 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
September 6
50% probability date
Last Spring Freeze
June 12
50% probability date
Growing Season
86 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
8,331
Higher = more heating needed
Cooling Degree Days
134
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
What May's climate means for you
May runs 42°F a year - peaking in July, coldest in January.
- Gardeners get about 86 frost-free days, with the last spring freeze near June 12 - plan the planting calendar around it, not the regional average.
- Energy bills track 8,331 heating and 134 cooling degree days a year, higher means the furnace or AC runs more.
- Comparing places to live? Line this city up against nearby cities and the national rankings. See rankings
These are 30-year NOAA normals (1991–2020) - the typical year, not a forecast for any specific season.
Climate Guides
Climate Insight: May, ID
Based on station USC00105685 feeding NOAA's 1991–2020 climate normals, May, Idaho averages 42°F a year, ranging from a mean daily high of 59°F to a mean daily low of 26°F. July is typically the warmest month of the year, while January is the coldest. Because these figures are thirty-year averages rather than any single year's readings, they describe the typical month, not a forecast for it.
Beyond temperature, May averages 8.5 inches of precipitation annually, predominantly as rainfall - a real factor for anyone planning to live, garden, or travel here. The frost-free season averages 86 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near June 12 and the first fall freeze near September 6. Turning to energy use, 8,331 heating degree days and 134 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, May scores 34/100 (Below Average), 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.
Frequently Asked Questions
What is the average temperature in May, ID? ▼
The average annual temperature in May, Idaho is 42°F. The warmest month averages 87°F (30°C) and the coldest averages 6°F (-14°C).
How much rain does May get? ▼
May receives 8.5 inches of precipitation annually. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for May? ▼
May has a climate comfort score of 34/100 (Below Average), milder than 1% of U.S. cities in the PlainClimate database.
When is the growing season in May? ▼
May has approximately 86 frost-free days per year, with the last spring freeze around June 12 and the first fall freeze around September 6.
How much energy does heating and cooling require in May? ▼
May has 8,331 heating degree days and 134 cooling degree days annually, a heating-dominated climate. See our <a href="/guides/reading-weather-data/" class="underline hover:text-brand-600">guide to reading weather data</a> for what these figures mean.
Where does this May climate data come from? ▼
NOAA U.S. Climate Normals v1.0.1 (1991-2020), from weather station USC00105685 near May.
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USC00105685. For informational purposes only.
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainClimate Editorial
Every figure on PlainClimate is rendered directly from NOAA 1991-2020 U.S. Climate Normals data, no number is typed in by an editor. This page draws directly on NOAA 1991-2020 U.S. Climate Normals data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.