You can have a mixed climate.

The Köppen climate classification is the most widely used in the 1954 Köppen–Geiger variant.

Check the following link: https://en.wikipedia.org/wiki/Climate_classification

Good luck.

Basins, watersheds, catchments sometimes are in more than one geology, physiographic area or climate. The best description to describe the mixed nature is more wordy, but also in many cases more appropriate, to give the reader a truer essence of the variable conditions. For instance, trying to average mountains that are snow dominated with lowland drier valley terrain into some intermediate or average wording is difficult, and would likely not do justice to the complexity. Sometimes an appropriate GIS figure can help show the complexity in topography, rainfall, vegetation types, drainage network, etc.

William F. Hansen The example you mentioned is the exact condition in my area of interest except that instead of being snowy, the mountain just receives heavier precipitation instead. The immediately adjacent regions also have significant precipitation however, it's the regions around the periphery of the area which create a huge difference. About 95% of the precipitation occurs in a single season (June-September) while the other seasons are normally close to being almost completely dry. I have three raingauge stations in the area, one of which is situated in the mountain region which records about 1500 mm rainfall. Another raingauge is located about 30 km from this mountain station but the precipitation there is 700 mm, similar to the final raingauge located at the periphery of the area which also records average precipitation in the order of 700 mm.

So what I understood from your answer is that it's better to explain the variability in precipitation in the area instead of just expressing it in terms of a single average value which doesn't represent the complexity of the hydrology in the area, am I right?

Jochen Hack I'm trying to choose a probability distribution for the Standardized Precipitation Index values that I have calculated. Some papers suggest that though a gamma distribution is usually used for this purpose, the climate of the area also plays a role in the selection of a distribution. In arid and semi-arid areas with a dominant single season rainfall and a lot of zero rainfall values, an extreme value distribution may be a better choice for SPI distribution fitting. This is why I want to identify the climate in my area which despite having a dominant single season rainfall with scanty rainfall in other season, has high variability in thr rainfall with a mountainous region receiving about 1500 mm annual average rainfall while the relatively low-lying regions receive only 700 mm rainfall.

I think you got my point. If you have access to GIS topographic data, you could show the mountain, the hydrologic boundaries of your “catchment”, the location of the raingauges. With only 3 raingauges, it is probably enough to fully explain the variability, but maybe enough to write generally. You might look up the orographic rainfall effect of mountains. If I remember right, for each 1000 feet in elevation change, air temperature cools 1 degree C (approximately anyway). When the storm comes in close to the dew point, it does not take much elevation change to condense the moisture into rainfall as the moist air is pushed up the mountain. I don’t know if there is anything useful in my Chattooga River report estimating boating upper river opportunity by comparing the short term upper stream gauge to the long term lower and much larger watershed stream gauge. I know you are probably evaluating an area in India, but if you pull up Technical Paper 40 of the USWeather Bureau, and could overlay the terrain, you could see that the west to east dominate air flow over mountains, dump rainfall heavily on the west side, and with most of the moisture gone, the east side of the mountains have lower to much lower rainfall, depending in part on the height of the mountains. You might consult a statistician, but with 3 rain gauges, probably best to write general conditions, but speaking to much higher to double the rainfall in mountains than lowlands.

Also best to state what you have, and period of rainfall record at the three stations. If you had 25, 50 or more years of record, you can say more with confidence than if you have less than 10 years of record.

Some countries have assembled rainfall frequency information for various uses, of rainfall were your special interest. You might look up the hydrologic condition paper I uploaded on Indian Creek in South Carolina on the National Forest. If you want to describe a watershed or catchment, many times if you dig deep, you can come up with quite a lot.

William F. Hansen Thank you for this explanation. I have prepared a topographic map with all the necessary additions as suggested in GIS. I clubbed it with a interpolated precipitation map which seems decent enough. The area is about 1,800 sq. km / 700 sq. miles.The highest grid resolution for 110 years of rainfall data in India is 0.25X0.25 degrees which gives me only 2 grid points within the area so I opted for the actual raingauge data which also has a decent record of 64 years. What I wanted from this data was to calculate the Standardized Precipitation Index at different time scales in order to represent the characteristics of the rainfall regime in the area but I'm facing another set of problems there such as getting 1-month SPI values as exactly zero in the month of July (highest monthly rainfall) across multiple years.

It is clear that cachments with different climates are big in size. So, you need to make watershed (catchment) delineation first and identify climate for each sub-basin. Let is take a Nile river. It has rather big catchment with varied climates. In this cased one needs to give description of sub-basins for each climate type.

Harsh--the spatial variation in annual precipitation you describe is similar to that of the mountainous Tahoe Basin (located in states of CA & NV in USA), for which I performed a water mass balance estimate as part of my PhD dissertation. The overall climate of the Tahoe Basin can be described as 'montane Mediterranean', where most precipitation falls (as rain and snow) in the winter months and very little falls in the summer months. Sounds like your study watershed has instead summer-dominated precipitation (unless in southern hemisphere).

I used normalized annual point precipitation indices to characterize annual precipitation over many years, and to help in estimation of areal precipitation over large areas (the lake, surrounding watershed, and whole basin areas). For the Tahoe Basin, it turns out that the variance of the annual time series of normalized annual precipitation decreases with increasing elevation in the basin (i.e. more inter-annual variability of normalized precip at low elevations than at high elevations).

James C. Trask Thank you for replying. My study area is similar to Tahoe Basin as the variance in the annual rainfall decreases with increasing elevation. And I have found that the effect of elevation is quite significant. I have decided to address the average rainfall in my area as a range (minimum at station 1 to maximum at station 2) instead of using a single average value. I have found some papers which do the same, one of which noted a range of 600 mm to 5000 mm average annual rainfall. I feel like this will do justice in explainin the rainfall regime in my study area.

Harsh--yes I agree, explicitly stating the spatial range of the mean annual precipitation is a good metric of the rainfall regime, conveying to the reader the large spatial variation of mean annual precipitation in your study area.

We have worked on characterizations, I hope you find our papers useful:

https://www.researchgate.net/publication/343981824_Analysis_of_climate_types_Main_strategies_for_sustainable_decisions_in_agricultural_areas_of_Carabobo_Venezuela

https://www.researchgate.net/publication/342055977_Application_of_multivariate_techniques_in_the_agricultural_lands_aptitude_in_Carabobo_Venezuela