Track rain and storms across Chiang Mai and the mountain valleys of northern Thailand. Updates every 5 minutes.
Chiang Mai sits in a mountain basin encircled by Doi Suthep and the Thanon Thong Chai Range. This landscape creates distinctive weather patterns: orographic lift brings heavy rainfall to western slopes, while the city basin can trap moisture and pollution. Storms frequently form along the ridgelines before descending into the Ping River valley.
The southwest monsoon brings heavy and persistent rain, with August–September averaging 200–250 mm each month. Mountain thunderstorms can cause flash floods along streams feeding into the Ping River. The old city's moat area and the low-lying Kad Farang district are especially at risk.
March–April is the notorious burning and haze season. Occasional thunderstorms help clear the smoke but can be intense. In November, the monsoon withdraws, with rainfall decreasing but still significant.
Cool, dry air from China brings comfortable temperatures. Rainfall falls below 20 mm per month. Morning fog in the basin is common, but rain is rare.
One tap, and the rain at that precise spot tells its own story—showing intensity, precipitation type, cloud and air temperatures, and live national alerts, while making even the smallest rain pockets easy to identify and compare.
Mountain trails around Doi Inthanon, Doi Suthep, and Mae Chaem become hazardous during heavy rain. Radar gives guides time to reroute or shelter groups before storms arrive.
Rice paddies and longan orchards in the surrounding plains rely on the monsoon rains. Radar helps farmers time irrigation and protect drying harvests from unexpected showers.
Chiang Mai’s large remote-worker community uses radar to plan motorbike commutes and outdoor co-working around afternoon storms.
Yi Peng and Songkran events require weather monitoring. Radar helps coordinators make safety decisions for lantern releases and outdoor celebrations.
Rain Viewer covers the Chiang Mai basin and surrounding mountains, extending north towards Chiang Rai and south to Lamphun. Mountain terrain can create radar shadows in deep valleys, but coverage of the populated basin and major highways is comprehensive.
“A little overenthusiastic at times with rain predictions, but it's accurate and spot on for radar images, and it's the one radar app I've kept and not uninstalled”
Duncan Stewart
I must update my feedback once again – this is still the best brain app in the app store. The issue I was experiencing was with my phone, not this top-tier app. One feature I particularly like is the widgets.
Jim Tigs
Radar covers the basin and main valleys well. Deep valleys behind high peaks may have reduced coverage, but storms approaching Chiang Mai city are tracked accurately.
Yes. Monitoring radar for prolonged heavy rainfall upstream (north of the city) provides early warning of rising river levels, usually 2–4 hours before flooding reaches central Chiang Mai.
Radar detects rainfall regardless of smoke. During haze season, radar can identify those much-needed rain showers that help improve air quality.
Chiang Mai’s rain is rapid, shaped by the terrain, and impossible to predict from a weekly forecast. The map updates every 5 minutes — often 2–5 minutes faster than other apps — so by the time a cell is crossing the Doi Suthep ridge, you’ve already spotted it coming.
Rain Viewer Essential gives you:
A 7-day forecast tells you July will be wet. Rain Viewer tells you whether the ridge is clear enough to leave for Pai now or wait two hours.
Track rain in Chiang Mai — free
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