74 photographs › At a glance
- Jan
- Feb
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- Apr
- May, shaded
- Jun, shaded
- Jul, shaded
- Aug, shaded
- Sep, shaded
- Oct, shaded
- Nov
- Dec
About the genus · Rhododendron
Rhododendron, from Ancient Greek ῥόδον (rhódon), meaning "rose", and δένδρον (déndron), meaning "tree", is a very large genus of about 1,024 species of woody plants in the heath family (Ericaceae). They can be either evergreen or deciduous. Most species are native to eastern Asia and the Himalayan region, but smaller numbers occur elsewhere in Asia, and in North America, Europe and Australia.
Quoted from Wikipedia, "Rhododendron", CC BY-SA 4.0.
Cultivation
Grouped as a temperate garden plant, listed under the genus Rhododendron in the archetype table, and Kew describes it as “epiphyte”, “temperate”.
Seasons
The rain rule reads a summer growing season: 70% of the median year's rain (2,464 mm of 3,330 mm) falls in May to October, warmer than the year (wet-season mean 21.3 °C against a yearly mean of 17.7 °C). Months are the habitat's, northern hemisphere; shifted six months for a southern-hemisphere collection: November to April.
Rain
3,330 mm in the median year at the habitat, 2,464 mm of it May to October. Wettest month September at 506 mm, driest month December at 87 mm. Across the grid cells of the range the year's total runs 2,605 mm to 4,601 mm, the 10th to 90th percentile of each cell's own year. The median of the cells' own yearly totals, 3,474 mm, is the year's rain at the top of the page; the 3,330 mm here is the median year's, the twelve monthly medians added, which the rain rule reads. Habitat calendar, northern hemisphere; median year across the grid cells of the range, CHELSA.
Light
Open sky over the habitat: 17 to 36 mol/m²/day across the year (daily light integral, median year across the grid cells of the range, CHELSA; the lowest 10th-percentile month across the cells is 13, the highest 90th-percentile month 38).
Warmth and air
Coldest: the 1st-percentile night over 44 years at a typical spot in the range is 3.7 °C, the absolute minimum -1.1 °C, 2 frost nights in 44 years (NASA POWER daily minima). Warmest: the 99th-percentile day is 29.2 °C. Monthly means: the coldest month's mean nightly low 7.5 °C in January (across the grid cells of the range 1.5 °C to 12.2 °C), the warmest month's mean daily high 25.6 °C in July (median year across the grid cells of the range, CHELSA). Cold floor: 3.7 °C, which is the 1st-percentile night over 44 years at a typical spot in the range (NASA POWER).
Relative humidity at the habitat: 64 to 68% across the year (monthly means, median year across the grid cells of the range, CHELSA). A figure about the air, saying nothing about how the plant takes water.
How this section is made
Each card states this species' habitat figures with their sources, and what two fixed rules read from them; nothing here says what the plant does, wants or tolerates. The rules · the terms.
Seasons. Read from the median year of CHELSA monthly rainfall and mean temperature across the grid cells of the range: the rain rule takes the smallest set of months carrying 70% of the rain and calls it winter when its mean is more than half a degree below the year's, summer when more than that above, and neither in between; the temperature rule, used only under 120 mm, names the cooler six months when they are at least a degree cooler than the other six. Months are shifted for the other hemisphere only where the temperature curve moves 4 °C or more and the habitat lies 10° or more from the equator. A reading of the curves, not an observation of the plant.
Rain. CHELSA monthly precipitation, median year across the grid cells of the range. The rain that falls where the species is recorded; nothing about how the plant takes water.
Light. CHELSA shortwave radiation at each envelope cell, a daily-mean flux taken to a daily total and converted at 2.07 mol of PAR per MJ. The sky over the habitat, measured; what reaches a plant under a rock, a shrub or a shade cloth is not.
Temperature. NASA POWER daily minima and maxima over 44 years at a typical spot in the range, lapse-corrected +548 m to its elevation; CHELSA monthly means, median year across the grid cells of the range. The cold floor is the 1st-percentile night named in its sentence. Not a measured survival limit for any plant in a pot.
Humidity. CHELSA relative humidity, median year across the grid cells of the range.
Group. Listed under the genus Rhododendron in the archetype table, and Kew describes it as “epiphyte”, “temperate”. A group is taken only where Kew's description of the species agrees with the table's listing. The table gives no figure and no prose; the cold floor is the habitat's alone.
Climate across the habitat
Habitat months, northern hemisphere
Mean daily high from 14 °C in Jan to 26 °C in Jul; mean nightly low from 8 °C in Jan and Feb to 19 °C in Jul and Aug. The cold quarter, Dec to Feb, is the three months around the coldest month's mean nightly low, centred on the 2 months in a row that tie for it. 3,330 mm of rain in the median year (the twelve monthly medians added), the wettest month Sep. The bands show the 10th to 90th percentile across 171 habitat cells. Over 44 years at a typical spot in the range (NASA POWER) the absolute minimum was -1.1 °C and the 99th-percentile day 29.2 °C; neither is dated to a month. Beneath: daily light integral and relative humidity through the year, each on its own scale.
Figures by month
| Figure | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day °C | 14 / 9–18 | 15 / 11–19 | 18 / 13–21 | 21 / 16–24 | 23 / 18–26 | 24 / 19–28 | 26 / 20–29 | 25 / 20–29 | 24 / 19–27 | 21 / 17–25 | 19 / 14–22 | 15 / 11–19 |
| Night °C | 8 / 2–12 | 8 / 3–13 | 11 / 6–15 | 14 / 9–18 | 16 / 11–21 | 18 / 12–23 | 19 / 13–25 | 19 / 13–24 | 18 / 12–23 | 15 / 10–20 | 12 / 7–17 | 9 / 3–14 |
| Rain mm | 88 / 51–214 | 170 / 92–275 | 184 / 113–245 | 219 / 158–292 | 358 / 274–521 | 460 / 353–687 | 438 / 246–718 | 478 / 329–770 | 506 / 309–651 | 224 / 107–562 | 118 / 53–396 | 87 / 46–248 |
| DLI | 17 / 13–22 | 19 / 15–24 | 25 / 20–30 | 29 / 26–33 | 30 / 28–33 | 31 / 29–33 | 36 / 33–38 | 33 / 30–34 | 28 / 27–30 | 25 / 21–28 | 19 / 16–24 | 17 / 13–21 |
| RH % | 65 / 60–73 | 66 / 62–73 | 65 / 62–72 | 66 / 63–71 | 66 / 64–71 | 67 / 64–70 | 66 / 64–70 | 68 / 65–70 | 68 / 65–71 | 67 / 62–73 | 65 / 60–72 | 64 / 59–73 |
How this section is made
Natural habitat
How this section is made
Photographs
Photographs: (c) Kiwi Shen, some rights reserved (CC BY) (2); (c) 雲一百香果, some rights reserved (CC BY); (c) Yinling Chen, some rights reserved (CC BY); (c) 曾昱承 Yu-Cheng Zeng, some rights reserved (CC BY) (2).
Related
Similar habitat climate The 6 nearest by mean daily high, mean nightly low and rain, month by month. How.
Dendropanax dentigerus Araliaceae Photo: CC BY, Cheng-Te Hsu
Diplazium maximum Athyriaceae Photo: CC BY, 林正文
Pilea plataniflora Urticaceae Photo: CC BY-SA, vrxz
Sedum actinocarpum Crassulaceae Photo: CC BY, Francisca Wu
Medinilla fengii Melastomataceae Photo: CC0, author not stated
Calanthe arisanensis Orchidaceae Photo: CC BY, 林正文Other Rhododendron 574 in the reference
Rhododendron aberconwayi Ericaceae Photo: Public domain, Daderot Rhododendron abietifolium Ericaceae Rhododendron acrophilum Ericaceae 
Rhododendron adamsii Sagan Dalya Photo: CC BY, Valentin Kosterin
Rhododendron adenogynum Ericaceae Photo: CC BY-SA, Kurt Stüber
Rhododendron adenopodum Ericaceae Photo: CC BY-SA, Ulf Eliasson
Rhododendron adenosum Ericaceae Photo: CC0, Daderot
Rhododendron aeruginosum Ericaceae Photo: CC BY, Siddarth Machado
Rhododendron aganniphum Ericaceae Photo: CC0, Daderot Rhododendron agathodaemonis Ericaceae 
Rhododendron alabamense Alabama azalea Photo: CC BY, Rob John
Rhododendron albiflorum White rhododendron Photo: CC0, author not stated all 575 ›Names & registers
Also known as Azalea elliptica; Rhododendron ellipticum; Rhododendron ellipticum var. leptosanthum; Rhododendron ellipticum var. tanakae; Rhododendron ellipticum var. tanakaii and 8 more. (GBIF Backbone)
Under another author Rhododendron catawbiense Hoffmanns. is an older name of this species, not Rhododendron catawbiense, a species of the reference; Rhododendron leptanthum Hayata is an older name of this species, not Rhododendron leptanthum, a species of the reference. (GBIF Backbone)
The record
Every figure here is derived from public data by a stated rule and names its source; nothing about this species is written for its page by a person or by AI, apart from the marked, credited quotations. How →
Where this page came from built 2026-10-22
gbif.species answeredasked 2026-10-22gbif.synonyms answeredasked 2026-10-22gbif.vernacular answeredasked 2026-10-22names fetched 2026-10-22wcvp.distribution answeredas of 2026-06-04gbif.occurrences answeredas of 2026-10-21GBIF occurrence download https://doi.org/10.15468/dl.hbdw64, of 2026-10-21; 8 records within 1 km of a botanic garden, herbarium or zoo left out (8 at a botanic garden or arboretum; Wikidata's list)climate answeredasked 2026-10-22climate.extremes answeredasked 2026-10-22NASA POWER (MERRA-2) daily 1981–2024, cell 25.00_121.250, lapse-corrected +548 m at 6.5 °C/kmwikidata answeredasked 2026-10-22wikipedia nothing to reportasked 2026-10-22inat.photos.wild answeredasked 2026-10-22from iNaturalist's open data of 2026-09-27: research-grade observations with an open-licence photograph, the 24 whose photographs iNaturalist received last (the open data holds no votes); filled 2026-10-22inat.photos.cultivated not askedgbif.media answeredasked 2026-10-22openalex not askednot yet asked for this reference; a later fill takes the papers from OpenAlex's snapshotEvery source is recorded as having answered, reported nothing, refused, failed, not been asked, or answered twice where one answer is taken (“not taken: two items answered”), and, for a source asked when this page was built, when: the figures are as the source held them that day; a source read from a file (Kew's World Checklist, a GBIF download) says "as of" the file's day instead; a row carried from an earlier build of the page names that build instead. Only “nothing to report” is ever shown as an absence. Records came from 33 datasets via GBIF.org; each carries its own licence.