Western China (Tibet, Xinjiang) 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 Apr–May, Oct.
Arid high plateau & desert
| Month | High °C | High °F | Rainy days | Verdict |
|---|---|---|---|---|
| January | 1.8 | 35 | 1% | Too cold |
| February | 3.8 | 39 | 1% | Too cold |
| March | 7.8 | 46 | 3% | Fair |
| April | 12.3 | 54 | 7% | Fair |
| May | 16.8 | 62 | 21% | Go |
| June | 20.4 | 69 | 46% | Fair |
| July | 19.7 | 67 | 65% | Too wet |
| August | 18.3 | 65 | 62% | Too wet |
| September | 16.5 | 62 | 41% | Go |
| October | 12.7 | 55 | 6% | Fair |
| November | 7.2 | 45 | 1% | Fair |
| December | 3.5 | 38 | 0% | 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.
December is the driest month, with rain on 0% of days and daytime highs near 3.5°C (38°F). July is the wettest, at 65%. The warmest month is June at 20.4°C (69°F); the coolest is January at 1.8°C (35°F). The record rules out too cold in Dec–Feb; too wet in Jul–Aug.