Brunei is demanding in every month. No month rates better than marginal on heat and rainfall together, so the trip is about tolerating the conditions rather than avoiding them.
Wet much of the year
| Month | High °C | High °F | Rainy days | Verdict |
|---|---|---|---|---|
| January | 28.2 | 83 | 73% | Too wet |
| February | 28.2 | 83 | 60% | Too wet |
| March | 28.8 | 84 | 64% | Too wet |
| April | 29.3 | 85 | 85% | Too wet |
| May | 29.4 | 85 | 87% | Too wet |
| June | 29.1 | 84 | 85% | Too wet |
| July | 29.0 | 84 | 80% | Too wet |
| August | 29.1 | 84 | 81% | Too wet |
| September | 29.0 | 84 | 89% | Too wet |
| October | 28.6 | 83 | 95% | Too wet |
| November | 28.6 | 83 | 97% | Too wet |
| December | 28.6 | 83 | 93% | 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.
February is the driest month, with rain on 60% of days and daytime highs near 28.2°C (83°F). November is the wettest, at 97%. Temperature barely moves all year — just 1.2°C between the warmest and coolest months — so rainfall, not heat, decides when to go. The record rules out too wet in Jan–Dec.