Published: July 2026
Southwest China Enters the Rainy Season
June marks the beginning of the main rainy season across Southwest China, including the key wild truffle-producing provinces of Yunnan and Sichuan.
According to public meteorological reports released during June, southern China officially entered its annual flood season, and several rounds of rainfall affected parts of Southwest China throughout the month. Rainfall intensity varied considerably between regions, with localized heavy rainfall events rather than uniform conditions across all production areas. (China Meteorological Administration)
For the Chinese black truffle (Tuber indicum), June is an important stage of underground development. Although harvest is still several months away, soil moisture accumulated during the summer will influence truffle growth during the months ahead.
Weather Observations
Based on publicly available weather information, our observations for June are as follows:
- The summer rainy season became established across much of Southwest China.
- Parts of Yunnan and Sichuan experienced several episodes of moderate to heavy rainfall during the month.
- Rainfall distribution remained uneven between different counties and mountain regions, meaning growing conditions may differ significantly even within the same province.
At this stage, it is too early to determine whether these weather patterns will result in a stronger or weaker truffle season.
What June Weather Means for Truffle Development
Based on the known biological cycle of Tuber indicum, June weather should be viewed as one part of a much longer growing cycle.
Adequate rainfall during early summer generally helps maintain soil moisture, which supports the development of underground fungal networks. However, weather conditions during August, September and October are usually more influential in determining:
- Final truffle size
- Internal quality
- Aroma development
- Percentage of premium export-grade truffles
For this reason, June rainfall alone should not be used to predict harvest volume or market prices.
Field Observation
As of the end of June:
- No commercial harvesting has begun in China’s major wild black truffle regions.
- No reliable production or quality data is currently available.
- Our supplier network has not yet reported any meaningful information regarding the upcoming harvest.
This is consistent with the normal seasonal cycle, as Chinese wild black truffles are typically harvested from late autumn through winter.
Market Watch
International buyers have begun making preliminary enquiries for the upcoming season, although most purchasing decisions are expected later in the year once harvest conditions become clearer. Assessment: this reflects the typical seasonal purchasing rhythm observed in prior years, when buyer commitments concentrate closer to harvest once field conditions are known — it is not based on confirmed intentions from this season’s buyers.
At present, there is no reliable evidence suggesting either an exceptionally abundant crop or a significant supply shortage.
Outlook for July
During July, Truffle Mountain will continue monitoring:
- Rainfall patterns across major production areas in Yunnan and Sichuan
- Temperature trends
- Extreme weather events that may affect mountain ecosystems
- Early observations from local suppliers
Our July update will focus on how continued summer weather may influence the development of the 2026/27 Chinese black truffle season.
Methodology
This report is based on publicly available meteorological information and seasonal observations.
Sources include:
- Public weather reports and meteorological information released by Chinese authorities.
- Publicly available news regarding weather events in Southwest China.
- Historical knowledge of the growth cycle of wild Chinese black truffles (Tuber indicum).
- Observations from the Truffle Mountain supplier network.
This report is intended to provide supply chain observations rather than official agricultural production statistics or harvest forecasts.
Regional Monitoring Dashboard
| Region | June Weather | Field Status | Harvest Status | Data Source |
|---|---|---|---|---|
| Yongren (Yunnan) | Moderate to heavy rain, locally torrential, occurred June 13–15 across central-eastern, western-edge, and southern-edge Yunnan; cumulative rainfall of 20–50mm reported, with localized thunderstorms | No field harvest observations available | Not started | Official Weather Data (Yunnan Meteorological Bureau) |
| Chuxiong (Yunnan) | Fell within the same June 13–15 regional rainfall system; per the National Climate Center’s 15–30 day outlook, precipitation across central-western Yunnan ran 20–50% above the seasonal average during June 8–23 | Monitoring | Not started | Official Weather Data (China Meteorological Administration) |
| Huize (Yunnan) | Located within the broader central-eastern Yunnan rainfall zone; county-level data not yet independently verified | Monitoring | Not started | Public Weather Data |
| Panzhihua (Sichuan) | Rainy season onset in late May 2026, close to the historical average; early June brought intermittent showers and thunderstorms typical of the Panxi region | Monitoring | Not started | Official Weather Data (Sichuan Meteorological Bureau) |
| Liangshan (Sichuan) | Rainy season onset in late May 2026, close to the historical average; scattered rain events continued into June | Monitoring | Not started | Official Weather Data (Sichuan Meteorological Bureau) |
Data Source Guide
| Source Type | Meaning |
|---|---|
| Official Weather Data | Sourced directly from provincial or national meteorological authorities (CMA, provincial bureaus) |
| Public Weather Data | Aggregated from public weather services; not independently verified at county level |
| Supplier Observation (Pending) | Awaiting confirmation from Truffle Mountain’s on-ground supplier network |
| Truffle Mountain Field Network (Not Yet Available) | Direct field data collection, not yet operational for this season |