Switzerland has no ideal window. No month clears the bar for comfortable travel outright, but Mar–May, Jul–Nov comes closest — rated fair rather than too hot, too cold or too wet.
Mild; summer warm & busy
| Month | High °C | High °F | Rainy days | Verdict |
|---|---|---|---|---|
| January | 2.7 | 37 | 43% | Too cold |
| February | 4.2 | 40 | 42% | Too cold |
| March | 9.0 | 48 | 47% | Fair |
| April | 13.4 | 56 | 46% | Fair |
| May | 17.5 | 64 | 56% | Fair |
| June | 20.9 | 70 | 60% | Too wet |
| July | 22.6 | 73 | 55% | Fair |
| August | 22.5 | 72 | 52% | Fair |
| September | 18.5 | 65 | 45% | Fair |
| October | 14.1 | 57 | 42% | Fair |
| November | 7.7 | 46 | 44% | Fair |
| December | 3.2 | 38 | 48% | Too cold |
Verdict combines mean daytime high with rainy-day frequency. “Rainy days” is the share of days in the month with at least 1 mm of rain.
February is the driest month, with rain on 42% of days and daytime highs near 4.2°C (40°F). June is the wettest, at 60%. The warmest month is July at 22.6°C (73°F); the coolest is January at 2.7°C (37°F). The record rules out too cold in Dec–Feb; too wet in June.