Climate Requirements for Growing Cashew

Cashew (Anacardium occidentale L.) is one of the most economically significant tropical nut crops in the world, cultivated across more than 28 countries in Africa, Asia, and the Americas. But growing cashew successfully is not just about finding available land – it is fundamentally about finding the right climate. The tree has clear preferences for temperature, rainfall patterns, altitude, sunlight, and seasonal timing, and when those conditions are well-matched, cashew can be remarkably productive. When they are not, even well-managed orchards fall short.

Optimal temperature range for cashew 🔗

Cashew is a tropical plant through and through. It thrives in warm conditions and, unlike many other fruit crops, is genuinely tolerant of heat. According to Tamil Nadu Agricultural University’s cultivation guidelines, the ideal temperature range for cashew is 20°C to 30°C, with an optimal mean annual temperature of 24-28°C. Within this range, trees grow vigorously, flower reliably, and produce well-filled nuts.

Cashew can also handle short bursts of intense heat. ECHO Community’s crop resource profile notes that cashew thrives at temperatures up to 40°C. However, there are important limits. LeafCon Agro’s agronomy documentation points out that temperatures above 36°C during the flowering and fruiting period can adversely affect fruit setting and retention. Research published in Scientia Horticulturae further clarifies that temperatures beyond 34°C combined with very low relative humidity (below 20%) can cause flower drying and direct yield losses. At the extreme end, fruit drop becomes a risk when temperatures exceed 42°C during the fruiting stage.

Cold sensitivity is equally important to understand. Cashew cannot tolerate frost, and prolonged exposure to temperatures below 20°C significantly slows growth and suppresses flowering. This is why commercial cashew cultivation is firmly anchored in tropical and subtropical zones.

Rainfall requirements: flexibility with a critical caveat 🔗

One of cashew’s most notable traits is its ability to grow across a wide spectrum of rainfall conditions. Pagacas’s agronomic reference notes that cashew can survive in areas with annual rainfall ranging from as low as 400 mm to as high as 4,000 mm. In practice, however, the most productive growing areas tend to receive between 600 mm and 1,500 mm of rainfall per year, with a well-defined dry season. The TNAU model cultivation profile recommends annual precipitation of 1,000 to 2,000 mm as ideal for commercial cashew production.

What matters even more than total rainfall is its distribution across the year. University of Florida IFAS Extension makes this point clearly: rainfall distribution throughout the year is just as important – if not more so – than the annual total. Heavy rainfall that is evenly spread year-round is actually unfavorable for cashew, even if the trees manage to grow and occasionally set fruit.

Why too much rainfall is a problem 🔗

Cashew requires a pronounced dry season of at least four months to produce its best yields. When excessive rainfall and high relative humidity coincide with the flowering period, the consequences are serious. LeafCon Agro’s practice notes document two major outcomes: flower and fruit drop, and a heavy incidence of fungal diseases that attack the inflorescence and developing fruits. In regions with very high annual rainfall (above approximately 2,000 mm), cashew trees also tend to grow slowly, produce smaller nuts, and become more susceptible to pests and pathogens.

Water stagnation around roots is equally damaging. Cashew does not tolerate waterlogging at any growth stage, so even in high-rainfall zones, well-drained soils and good field drainage are non-negotiable.

Altitude and its influence on cashew performance 🔗

Cashew is primarily a low-elevation crop. TNAU’s cultivation guidelines restrict the distribution of cashew to altitudes up to 700 m above mean sea level, where temperatures do not fall below 20°C for prolonged periods. Pagacas notes that in exceptional cases – such as parts of Mexico, Brazil, Venezuela, and Tanzania – cashew plantations are found up to 1,000 m, but these are not typical of productive commercial cultivation.

The reasoning is straightforward: as altitude increases, temperatures drop. This pushes growing conditions outside the optimal thermal range, slows tree growth, and reduces yield. The same source confirms that the higher the elevation at which cashew is grown relative to sea level, the slower the tree grows and the lower the yield. Coastal belts at low elevations remain the most consistently productive environments for cashew globally.

Sunlight: cashew is not shade-tolerant 🔗

Cashew is a full-sun crop with no tolerance for shade. University of Florida IFAS Extension is explicit on this point: canopy exposure to full sunlight is required for optimum and reliable flowering. Shading reduces photosynthetic efficiency, suppresses flower development, and lowers overall productivity.

Cloud cover is also a meaningful concern. Pagacas’s agronomy reference identifies cloud cover as an important indicator for cashew suitability, noting that the suitable value for growing areas is 3 to 5 tenths, with 5 tenths being the upper limit. Beyond this, cloudy conditions reduce pollination efficiency and create favorable conditions for the outbreak of insect pests and diseases. Regions with consistently overcast skies – even if temperatures and rainfall are otherwise suitable – are not well-suited for high-yield cashew production.

Minimum sunshine hours also matter. Productive cashew regions typically receive at least 2,000 hours of sunshine per year, which supports the long flowering and fruiting season the crop requires.

The critical role of the dry season during flowering and fruit set 🔗

Perhaps the single most important climate factor for cashew productivity is the timing and quality of the dry season. Cashew trees follow a natural cycle: they accumulate nutrients and build canopy during the wet season, then flower and fruit during the dry season. Pagacas describes this adaptation clearly – as the dry season begins, the tree shifts its energy from vegetative growth to reproductive development, producing flowers and fruits favorably when conditions are dry.

Jain Irrigation’s agronomic analysis reinforces this: cashew needs a climate with a well-defined dry season of at least four months to produce the best yields. Coincidence of excessive rainfall and high relative humidity with flowering results in flower and fruit drop, and heavy incidence of fungal disease.

How humidity affects cashew flowers and fruit 🔗

Pagacas notes that cashew trees are suited to a relative air humidity of 65 to 80%. During the flowering and fruiting period specifically, lower relative humidity is better – it promotes healthier flower development and reduces disease pressure. High humidity during this phase negatively affects both the quantity and quality of production.

There is, however, one nuanced exception. In areas with very low rainfall, moderately higher humidity during flowering can actually be beneficial – it helps the tree manage water requirements and survive periods of moisture stress toward the end of the dry season, when soil water availability is lowest.

Wind as a supporting factor 🔗

Cashew is largely grown along coastal belts, which exposes trees to consistent airflow throughout the season. Pagacas highlights that wind plays an important role in pollen dispersal and cross-pollination in cashew. The optimal wind speed for cashew-growing areas is estimated at 2 to 25 km/h. Gentle wind aids pollination and helps manage humidity around the flower clusters. However, high-velocity winds cause flower and young fruit drop, which directly reduces yield. This is why exposed hilltops or cyclone-prone areas require careful site assessment before establishing a cashew plantation.

Putting it all together: the ideal climate profile for cashew 🔗

When the various climate factors are combined, a clear picture emerges of what cashew needs to perform at its best. The ideal growing environment features warm temperatures consistently in the 24-28°C range, annual rainfall between 1,000 and 2,000 mm concentrated in a distinct wet season, a dry season of at least four months that coincides with flowering and fruit development, full sunlight exposure, and low to moderate humidity during the reproductive phase. Altitudes should remain below 600-700 m to ensure temperatures stay within the productive range throughout the year.

This profile explains why tropical coastal regions – particularly in India, West Africa, Vietnam, and Brazil – have become the world’s dominant cashew-producing areas. These regions naturally deliver the seasonal rhythm that cashew depends on, and their low-elevation coastal topography provides consistent warmth and air circulation. A planting guide from the Hawaii Department of Agriculture also confirms that in ideal scenarios, rainfall between roughly 1,000 to 2,000 mm and a prolonged dry season play important roles in achieving optimum growing conditions – consistent with the experience of cashew-growing nations worldwide.

Understanding and matching these climate requirements before establishing a cashew orchard is not optional – it is the foundation of the entire production system. A site with the right climate minimizes disease risk, supports reliable flowering, and sets up every subsequent management decision for success.

What do you think? Given that cashew requires a distinct dry season during flowering, how do you think farmers in regions with irregular or shifting rainfall patterns should adapt their orchard management to protect yields? And with rising temperatures linked to climate change, do you think current cashew-growing regions will remain suitable in the coming decades – or will cultivation need to shift to new areas?

References

1. https://agritech.tnau.ac.in/banking/nabard_pdf/Plantation%20and%20Horticulture/2.%20Cashewnut_Cultivation.pdf
2. https://www.echocommunity.org/en/resources/09e3eede-d735-42cf-b7b4-e35c27942d9a
3. https://www.leafconagro.com/cashew-nut-agro-nomia-practice/
4. https://www.sciencedirect.com/science/article/abs/pii/S0304423823001310
5. https://en.pagacas.com/cashew-climate-soils-and-nutrients-blo86
6. https://ask.ifas.ufl.edu/publication/HS377
7. https://www.jains.com/Company/news/blog/HOWMUCHWATERDOESMYCROPNEEDPart2PerennialCrops1Cashew.htm
8. https://dab.hawaii.gov/wp-content/uploads/2018/12/Cashew-Trees-in-Hawaii-Guide.pdf