Guyana has no ideal window. No month clears the bar for comfortable travel outright, but Feb–Mar, Sep–Oct comes closest — rated fair rather than too hot, too cold or too wet.
Wet Dec–Mar (S. summer)
| Month | High °C | High °F | Rainy days | Verdict |
|---|---|---|---|---|
| January | 27.3 | 81 | 62% | Too wet |
| February | 27.3 | 81 | 55% | Fair |
| March | 27.6 | 82 | 47% | Fair |
| April | 28.1 | 83 | 58% | Too wet |
| May | 27.9 | 82 | 83% | Too wet |
| June | 27.6 | 82 | 96% | Too wet |
| July | 27.8 | 82 | 94% | Too wet |
| August | 28.4 | 83 | 84% | Too wet |
| September | 28.8 | 84 | 56% | Fair |
| October | 28.8 | 84 | 56% | Fair |
| November | 28.4 | 83 | 73% | Too wet |
| December | 27.8 | 82 | 75% | Too wet |
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.
March is the driest month, with rain on 47% of days and daytime highs near 27.6°C (82°F). June is the wettest, at 96%. Temperature barely moves all year — just 1.5°C between the warmest and coolest months — so rainfall, not heat, decides when to go. The record rules out too wet in Apr–Aug, Nov–Jan.