Very light rain of droplets under 0.5 mm falling slowly from low stratus cloud, common in South Asian hill stations and behind winter western disturbances.
BasicsWhat is Drizzle?
Drizzle is precipitation made of very small water droplets — conventionally those under about 0.5 mm across — falling so slowly and so densely packed that they seem to hang in the air rather than fall through it. The distinction from rain is not about how much water reaches the ground but about drop size and fall speed. A raindrop from a monsoon cumulonimbus can be several millimetres wide and hits hard enough to feel individually. Drizzle arrives as a fine wet film: you notice your shirt is damp before you notice it is raining.
In South Asia, drizzle is the minority form of rain. The overwhelming majority of the region’s water arrives as convective downpours during the southwest monsoon. But drizzle has its own seasons and its own places here, and in those places it dominates the weather for days at a time.
The languages of the region mark the difference. Hindi separates phuhaar, the fine spray, from baarish and bauchhar, the proper rain and the shower. Urdu uses phuwaar the same way. Bengali has ilshe guri, the fine drizzle that folk usage ties to the hilsa season. The vocabulary exists because the experience is distinct: drizzle is weather you live through rather than shelter from.
How drizzle forms
Rain and drizzle are made in different kinds of cloud. Rain generally needs deep convection: strong updraughts carry droplets high, where they grow large before the updraught can no longer hold them.
Drizzle comes from shallow, layered cloud — stratus and stratocumulus — where the updraughts are feeble, measured in centimetres per second rather than metres. Droplets in such a cloud grow only by bumping into one another and merging, a slow process known as the warm rain path because no ice phase is involved. Given enough time in a moist cloud the drops reach drizzle size and begin to settle out, but they never come close to raindrop size.
The air beneath the cloud matters too. A small drop has a large surface area for its volume and evaporates quickly, so if the layer below cloud is dry the drizzle never arrives — it evaporates on the way down as virga, which is why a radar image or a forecast can show precipitation that nobody on the ground feels. A capping temperature inversion helps by keeping the cloud shallow and the moisture trapped beneath it, which is exactly the set-up over the northern plains on a grey winter day.
Drizzle in South Asia
Hill stations. Where cloud sits directly on a slope, drizzle and mist stop being separate things. Shillong, Darjeeling, Mussoorie, Munnar and Ooty can go days in the wet season without the cloud lifting — everything permanently damp, no rain heavy enough to count, and no dry spell either.
Behind western disturbances. From December to March, the eastward-moving troughs that bring winter rain to Pakistan and north India rarely arrive or depart cleanly. The main rain band is often preceded and followed by hours of light drizzle under a low overcast across Punjab, Haryana, Delhi and western Uttar Pradesh.
The northeast monsoon. October to December over coastal Tamil Nadu and southeastern Andhra Pradesh brings grey spells of steady light rain, but depressions and cyclones from the Bay of Bengal also contribute significantly to the season’s rainfall, and heavy falls are frequent.
The edges of the monsoon. On the Konkan and Kerala coasts, the days around onset and withdrawal — and the breaks between active spells — frequently bring drizzle from the low cloud left behind when deep convection shuts down.
Winter in the eastern plains. Across Bangladesh and West Bengal, strong overnight inversions build shallow stratus that sometimes yields light drizzle alongside dense morning fog. Coastal Sindh sees something similar from low cloud drifting in off the Arabian Sea.
Why drizzle matters more than its rainfall total suggests
Roads. The most dangerous rain on a South Asian road is often the lightest. Weeks of dry weather leave a film of oil, rubber and dust on the surface; light rain lifts that film without washing it away, and the result is more slippery than a heavy shower that flushes the road clean. Two-wheeler riders feel it first.
Air quality. A heavy shower scavenges particulates efficiently and visibly clears the air. Drizzle often does not. Worse, light rain paired with very high humidity can make haze thicker rather than thinner, because many pollution particles absorb water and swell, scattering more light than they did dry. A drizzly winter morning in the Indo-Gangetic plain can have worse visibility and a worse AQI than the dry day before it.
Agriculture. Prolonged damp is a different problem from heavy rain. Around the rabi harvest in Punjab, Haryana and Sindh, days of drizzle keep standing wheat and cut grain from drying, encourage fungal disease, and complicate threshing — none of which registers as a meaningful rainfall figure.
Measuring drizzle and reading the forecast code
Drizzle defeats the instruments. A standard tipping-bucket gauge records nothing until enough water accumulates to tip the bucket, so hours of drizzle can log as zero or as a trace — the category meteorological services use for amounts too small to measure, below a tenth of a millimetre.
Radar does no better. The energy a drop returns to a radar scales with roughly the sixth power of its diameter, so a drizzle droplet reflects a vanishingly small fraction of what a large raindrop does. Drizzle can soak a city while barely registering on the radar picture, which is the main reason app forecasts and lived experience disagree on damp grey days.
In the WMO weather codes behind most forecast displays, including the ones on this site, drizzle gets its own band: light, moderate and dense drizzle are codes 51, 53 and 55, with freezing drizzle at 56 and 57.
Frequently asked questions
What is the difference between drizzle and light rain? Drop size and origin. Drizzle droplets are under about 0.5 mm and come from shallow stratus cloud; light rain has larger, more widely spaced drops and usually falls from deeper cloud.
Can drizzle cause flooding? Rarely on its own, but it contributes. Drizzle that continues for many hours keeps soil saturated, so when a genuine downpour follows, runoff is faster and flash flooding more likely. In the hills, days of drizzle raise landslide risk without a single intense burst.
Why does the forecast show rain when nothing is falling outside? Either the precipitation is evaporating before it reaches the ground as virga, or it is genuinely drizzling at a rate too low to register as rain until you have been outside for a few minutes.
Is drizzle common during the monsoon? Less than people expect. Monsoon rain is mostly convective and heavy. Drizzle belongs to the quieter phases — around onset and withdrawal, during breaks in the rains, and persistently in the hills where cloud rests on the terrain.
Where can I check whether drizzle is expected in my city? Every city page on Mausam Online shows hourly precipitation and the weather code behind it, so you can tell persistent light rain from a passing shower. Drizzle-prone locations include Shillong, Darjeeling, Chennai, Mussoorie, Munnar and Delhi.