April is one of the cooler months of the year in Boise, with average highs near 15°C and lows around 2.3°C (mean 8.7°C). It is about average for rainfall, averaging 36 mm of rainfall and 59% relative humidity across the period.
April is one of the cooler months of the year in Boise. Across 45 years of records, the warmest April in Boise was 1987 — when the month averaged 12.7°C — while the coldest was 2011 at 5°C. Typical April days reach 15°C with nights near 2.3°C. The long-term April temperature trend is broadly flat.
April is about average for rainfall in Boise, averaging 36 mm of rainfall. The wettest April on record was 1990 with 63 mm, while the driest was 2008 at 12 mm.
Relative humidity in Boise during April averages 59%. The most humid April was 1993 at 68%, and the least humid was 1987 at 49%.
April receives about 5.5 kWh/m²/day of solar energy in Boise. The sunniest Aprils were 2015 and 2021 at 6.3 kWh/m²/day, and the cloudiest were 2003 and 2011 at 4.9.
Average wind speed in Boise during April is 2.4 m/s. The windiest April was 1984 at 3 m/s, while the calmest were 1983 and 2025 at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 8.8°C | 8.6°C | 8.8°C | 8.7°C | 8.5°C | -0.3°C |
| Avg High | 15.4°C | 14.7°C | 15.2°C | 14.9°C | 15.0°C | -0.4°C |
| Avg Low | 2.2°C | 2.5°C | 2.4°C | 2.4°C | 2.1°C | -0.1°C |
| Avg Rain | 33 mm | 43 mm | 31 mm | 39 mm | 33 mm | +1 mm |
April temperatures in Boise have risen by about 0.6°C between 1981–1985 and 2021–2025.
April has ranged from a record low of -5.7°C (1997) to a record high of 30.8°C (1992).
Rainfall in April is about average for rainfall, averaging 36 mm, with a wettest year of 63 mm.
A good time to visit Boise
April is a good time to visit Boise, with days averaging 15°C and nights around 2.3°C (mean 8.7°C, cooler than Boise's yearly average) and moderate rainfall. August and July are marginally more temperate, but April still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 16.0°C | 9.4°C | 2.9°C | 24.9°C | -2.2°C | 22 mm | 61% | 2 m/s | 6 |
| 2024 | 15.2°C | 8.9°C | 2.6°C | 24.0°C | -2.3°C | 45 mm | 62% | 2.4 m/s | 5.9 |
| 2023 | 13.4°C | 7.3°C | 1.2°C | 29.0°C | -4.6°C | 27 mm | 62% | 2.6 m/s | 5.2 |
| 2022 | 12.7°C | 6.6°C | 0.5°C | 23.8°C | -4.2°C | 62 mm | 57% | 2.7 m/s | 5.2 |
| 2021 | 16.4°C | 9.5°C | 2.7°C | 27.1°C | -4.1°C | 17 mm | 50% | 2.1 m/s | 6.3 |
| 2020 | 16.1°C | 9.4°C | 2.8°C | 30.1°C | -3.8°C | 26 mm | 55% | 2.2 m/s | 6.2 |
| 2019 | 15.6°C | 9.8°C | 3.9°C | 26.1°C | -1.2°C | 51 mm | 64% | 2.5 m/s | 5.3 |
| 2018 | 15.5°C | 9.3°C | 3.0°C | 29.4°C | -4.1°C | 35 mm | 60% | 2.6 m/s | 5.4 |
| 2017 | 12.8°C | 7.3°C | 1.8°C | 19.5°C | -3.3°C | 59 mm | 66% | 2.5 m/s | 5.2 |
| 2016 | 18.3°C | 11.8°C | 5.2°C | 27.9°C | -0.1°C | 32 mm | 57% | 2.4 m/s | 6.1 |
| 2015 | 15.6°C | 8.8°C | 1.9°C | 25.6°C | -2.8°C | 20 mm | 54% | 2.5 m/s | 6.3 |
| 2014 | 15.1°C | 8.6°C | 2.2°C | 23.7°C | -2.2°C | 41 mm | 58% | 2.3 m/s | 6 |
| 2013 | 14.9°C | 8.4°C | 1.8°C | 25.5°C | -3.9°C | 24 mm | 54% | 2.8 m/s | 5.9 |
| 2012 | 16.9°C | 10.3°C | 3.7°C | 30.3°C | -3.6°C | 43 mm | 58% | 2.3 m/s | 5.4 |
| 2011 ❄️ | 10.8°C | 5.0°C | -0.8°C | 20.3°C | -4.4°C | 47 mm | 65% | 2.5 m/s | 4.9 |
| 2010 | 13.4°C | 7.3°C | 1.2°C | 25.6°C | -4.9°C | 42 mm | 60% | 2.8 m/s | 5 |
| 2009 | 14.4°C | 7.9°C | 1.5°C | 28.1°C | -4.6°C | 26 mm | 58% | 2.6 m/s | 5.8 |
| 2008 | 12.6°C | 6.1°C | -0.4°C | 24.7°C | -4.5°C | 12 mm | 55% | 2.6 m/s | 5.7 |
| 2007 | 16.1°C | 9.6°C | 3.1°C | 29.6°C | -2.6°C | 29 mm | 55% | 2.4 m/s | 5.7 |
| 2006 | 14.7°C | 8.8°C | 2.9°C | 23.8°C | -2.8°C | 57 mm | 65% | 2.3 m/s | 5.3 |
| 2005 | 15.6°C | 8.9°C | 2.2°C | 23.5°C | -3.9°C | 34 mm | 57% | 2.6 m/s | 5.1 |
| 2004 | 17.6°C | 10.9°C | 4.2°C | 27.6°C | -2.2°C | 17 mm | 53% | 2.1 m/s | 6 |
| 2003 | 13.4°C | 7.9°C | 2.4°C | 24.0°C | -2.9°C | 44 mm | 62% | 2.2 m/s | 4.9 |
| 2002 | 15.4°C | 8.9°C | 2.4°C | 23.5°C | -2.2°C | 31 mm | 56% | 2.4 m/s | 5.7 |
| 2001 | 14.1°C | 7.9°C | 1.7°C | 27.5°C | -3.3°C | 34 mm | 56% | 2.1 m/s | 5.2 |
| 2000 | 17.9°C | 10.9°C | 3.9°C | 29.2°C | -0.4°C | 28 mm | 57% | 2.3 m/s | 5.7 |
| 1999 | 13.8°C | 7.2°C | 0.5°C | 24.3°C | -4.5°C | 17 mm | 58% | 2.4 m/s | 5.8 |
| 1998 | 14.1°C | 8.1°C | 2.0°C | 27.0°C | -2.8°C | 29 mm | 62% | 2.1 m/s | 5.6 |
| 1997 | 12.8°C | 7.1°C | 1.5°C | 22.5°C | -5.7°C | 47 mm | 65% | 2.4 m/s | 5.4 |
| 1996 | 14.2°C | 8.4°C | 2.5°C | 25.9°C | -2.3°C | 53 mm | 62% | 2.3 m/s | 5.4 |
| 1995 | 13.2°C | 7.4°C | 1.6°C | 21.3°C | -3.3°C | 45 mm | 65% | 2.5 m/s | 5.3 |
| 1994 | 16.8°C | 10.4°C | 4.1°C | 29.4°C | -2.4°C | 37 mm | 56% | 2.3 m/s | 5.3 |
| 1993 | 12.4°C | 6.9°C | 1.3°C | 19.1°C | -2.3°C | 61 mm | 68% | 2.2 m/s | 5 |
| 1992 | 18.3°C | 11.5°C | 4.7°C | 30.8°C | -2.3°C | 30 mm | 52% | 2.3 m/s | 5.4 |
| 1991 | 12.6°C | 6.8°C | 1.0°C | 21.8°C | -4.7°C | 46 mm | 61% | 2.3 m/s | 5.3 |
| 1990 🌧️ | 18.6°C | 12.0°C | 5.3°C | 27.6°C | -3.8°C | 63 mm | 55% | 2.2 m/s | 5.5 |
| 1989 | 16.7°C | 10.1°C | 3.5°C | 25.9°C | -1.9°C | 17 mm | 60% | 2.1 m/s | 5.7 |
| 1988 | 17.4°C | 10.3°C | 3.2°C | 27.2°C | -3.8°C | 41 mm | 54% | 2.5 m/s | 5 |
| 1987 🔥 | 20.5°C | 12.7°C | 4.8°C | 30.4°C | -2.1°C | 13 mm | 49% | 2.5 m/s | 6 |
| 1986 | 14.2°C | 7.8°C | 1.5°C | 26.8°C | -2.9°C | 40 mm | 64% | 2.6 m/s | 5.5 |
| 1985 | 17.7°C | 10.6°C | 3.5°C | 28.3°C | -3.7°C | 18 mm | 54% | 2.2 m/s | 6.2 |
| 1984 | 12.2°C | 6.3°C | 0.4°C | 25.7°C | -3.2°C | 44 mm | 66% | 3 m/s | 5.1 |
| 1983 | 12.1°C | 6.5°C | 0.9°C | 19.5°C | -5.3°C | 46 mm | 64% | 2 m/s | — |
| 1982 | 12.1°C | 5.9°C | -0.3°C | 21.5°C | -4.3°C | 31 mm | 61% | 2.4 m/s | — |
| 1981 | 15.7°C | 9.2°C | 2.6°C | 27.1°C | -3.8°C | 46 mm | 60% | 2.2 m/s | — |
Actual recorded April data for each year, 1981–2025 — sourced from NASA POWER.
The average high in April is around 15°C with lows near 2.3°C (mean 8.7°C), based on 45 years of NASA POWER data.
April averages 36 mm of rainfall in Boise, about average for rainfall. The wettest on record was 63 mm in 1990.
The hottest April reached 30.8°C in 1992. The coldest dipped to -5.7°C in 1997.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average April temperatures have risen by about 0.6°C. Daytime highs moved from 14°C to 14.7°C and overnight lows from 1.4°C to 2°C over the same span.
April is one of the cooler months of the year in Boise and about average for rainfall, so plan for around 15°C daytime highs and 2.3°C at night.
Not quite — April is the 6th coolest month in Boise, averaging 8.7°C.
For April in Boise, pack warm layers and a jacket for chilly mornings, with typical highs of 15°C and lows of 2.3°C.
Relative humidity in April averages 59% — moderately humid.
Average wind speed in April is 2.4 m/s. The windiest April on record averaged 3 m/s (1984).
The wettest April on record was 1990 with 63 mm. On average, April sees 36 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Boise behaves each April, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for April specifically, along with year-by-year records and how the month has changed over the decades.
