Best time to visit Boise
May is the best time to visit Boise for general sightseeing, with average highs of 23 °C and about 6 wet days. The comfortable season runs roughly May to June.
It depends what you are going for
One month rarely wins on everything. These are the best months on each measure taken on its own.
| If you want | Best month | On that measure |
|---|---|---|
| Sightseeing and walking | May | comfort 92/100 |
| The least cloud | July | 21 % average cloud cover |
| The least rain | July | 3 mm |
| Warmth | July | 34 °C |
| Cooler weather | December | 3.9 °C |
Ranked by comfort
| # | Month | Comfort / 100 | Avg high | Wet days |
|---|---|---|---|---|
| 1 | May | 92 | 23 °C | 6 |
| 2 | September | 88 | 27 °C | 2 |
| 3 | October | 87 | 19 °C | 4 |
| 4 | June | 86 | 28 °C | 3 |
| 5 | April | 74 | 17 °C | 7 |
| 6 | August | 70 | 33 °C | 1 |
| 7 | July | 68 | 34 °C | 1 |
| 8 | March | 55 | 13 °C | 9 |
| 9 | November | 48 | 9.8 °C | 8 |
| 10 | February | 36 | 7.4 °C | 7 |
| 11 | January | 29 | 4.1 °C | 10 |
| 12 | December | 28 | 3.9 °C | 10 |
When to think twice
December scores lowest with about 10 wet days and highs near 3.9 °C. That does not make it a bad month — it depends entirely on what you are travelling for. The numbers are all here; the judgement is yours.
The full year
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 4.1 °C | 46 mm | 62 % |
| February | 7.4 °C | 31 mm | 59 % |
| March | 12.7 °C | 36 mm | 59 % |
| April | 17.0 °C | 32 mm | 54 % |
| May | 22.6 °C | 31 mm | 49 % |
| June | 27.7 °C | 18 mm | 38 % |
| July | 33.6 °C | 3 mm | 21 % |
| August | 33.0 °C | 3 mm | 22 % |
| September | 27.2 °C | 11 mm | 28 % |
| October | 18.7 °C | 22 mm | 40 % |
| November | 9.8 °C | 35 mm | 56 % |
| December | 3.9 °C | 50 mm | 62 % |
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: comfort score, beach score, season boundaries. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.