Latvia has two good windows: May and September. They sit either side of the season the climate record rules out, which is why the shoulder months matter here. The recommended window is May–Sep.
Cold; brief mild summer
| Month | High °C | High °F | Rainy days | Verdict |
|---|---|---|---|---|
| January | -2.4 | 28 | 46% | Too cold |
| February | -2.2 | 28 | 41% | Too cold |
| March | 2.3 | 36 | 37% | Too cold |
| April | 9.5 | 49 | 35% | Fair |
| May | 15.2 | 59 | 37% | Go |
| June | 18.7 | 66 | 45% | Fair |
| July | 21.4 | 71 | 48% | Fair |
| August | 20.7 | 69 | 46% | Fair |
| September | 16.2 | 61 | 40% | Go |
| October | 9.5 | 49 | 48% | Fair |
| November | 3.3 | 38 | 48% | Too cold |
| December | -0.6 | 31 | 49% | 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.
April is the driest month, with rain on 35% of days and daytime highs near 9.5°C (49°F). December is the wettest, at 49%. Temperature swings hard across the year — 23.8°C between July (21.4°C / 71°F) and January (-2.4°C / 28°F) — so packing for the wrong month is the main risk. The record rules out too cold in Nov–Mar.