TORONTO · LIVE
UTCI · thermal comfort
COOLHOT

Microclimate · Surface & energy · Wind · Daylight · Grid

See the
microclimate
before you build it.

CityDigitalTwin physically simulates how heat, wind, sun, building energy, and the power grid behave across a whole city — so architects, planners, and utilities can design cooler, healthier, more resilient places.

Trusted by
Ramboll WXY Hydro-Québec Arizona State University KAUST University of Sydney

Why CityDigitalTwin

Real physics. Not a proxy.

A new wave of tools predicts urban climate with AI models trained on simulation data — fast, but an approximation of an approximation, and unreliable the moment your design leaves their training set. CityDigitalTwin takes the other path: we solve the governing equations themselves, on GPUs, so real physics runs at the speed you'd expect from a shortcut.

Turbulent flow — LES momentum

ρ ( ∂u/∂t + (u·∇)u ) = −∇p + ∇·[(μ + μt)∇u] + f

Heat transport — air, surfaces, radiation

ρcp ( ∂T/∂t + u·∇T ) = ∇·(k∇T) + q̇rad

Building energy balance — every building, every hour

HVAC = Q̇envelope + Q̇solar + Q̇internal + Q̇ventilation

Solved on every cell, every timestep — 956 million cells for all of Toronto, in a few hours on one GPU.
AI-surrogate tools
CityDigitalTwin
Trained on someone else's simulations
Solves the equations, every run
Unreliable outside the training data
Valid for any geometry, any climate
A picture of a plausible answer
Fields you can inspect, chart, and export
Hard to defend in front of a reviewer
Physics you can stand behind

Validated against field measurements and reference solvers — validation studies in preparation for publication.

One platform, every scale

From street-level heat to the power grid.

Most tools solve one slice of the urban climate problem. CityDigitalTwin couples them — microclimate, energy demand, and grid response in a single, physics-based model.

UTCI thermal-comfort map over downtown Toronto in CityDigitalTwin

Urban microclimate

Heat-island mapping, air temperature, and thermal-comfort (UTCI) across every street and courtyard.

UTCI · MRT · Heat
Per-building thermal loads in CityDigitalTwin

Building energy

Whole-city UBEM for heating, cooling, and HVAC loads — building by building, hour by hour.

UBEM · HVAC · Loads
Pedestrian-level wind-speed field in CityDigitalTwin

Wind & comfort

Pedestrian wind comfort and safety, ventilation corridors, and gust risk around towers.

CFD · Pedestrian
Sun-hours map on buildings and streets in CityDigitalTwin

Solar & shading

Solar radiation, daylight, and shadow studies to place mass, glazing, and green roofs precisely.

Sun hours · Daylight · SVF
Per-building carbon emissions map in CityDigitalTwin

Carbon & renewables

Track emissions and size PV, vegetation, and green infrastructure against real climate data.

CO₂e · PV · Green
Automatic georeferenced 3D city model in CityDigitalTwin

3D city model

An automatic, georeferenced digital twin — buildings, roads, trees, grass, and water — ready to simulate.

Context · Terrain · Vegetation

The digital twin

Your city, physically simulated.

Upload your 3D city model — or generate one for anywhere on Earth — pick real weather, and run coupled microclimate and building-energy physics on GPU. Then explore every result right in the browser.

  • Interactive 3D and map views of every field — UTCI, MRT, air temperature, wind, surface temperature, energy, sun hours, daylight, SVF
  • Slice at any height, inspect any point, chart any building over time
  • Compare up to six design scenarios side by side, with difference maps
  • Generate PDF reports — pedestrian-wind planning studies, scenario comparisons — and export raw data (VTK, CSV)
CityDigitalTwin · Toronto · UTCI [°C]
Whole-city UTCI thermal-comfort field over Toronto in the CityDigitalTwin viewer
GRID 3813×125×2007 · 956M CELLS119,561 BUILDINGS · A FEW HOURS ON ONE GPU

How it works

From anywhere on Earth to insight.

The whole workflow is self-serve, in the browser — no desktop software, no consultants, no hand-offs.

01

Build the twin

Upload your own 3D model, or generate one for any place on Earth — buildings, roads, trees, grass, and water, georeferenced automatically.

02

Pick the weather

Historical years, design days, or a real forecast up to 16 days ahead — so you can simulate next week's heatwave before it arrives.

03

Run the physics

Coupled microclimate and building-energy solvers run on a cloud GPU fleet that scales to your case — a courtyard or a whole city.

04

Explore & compare

Slice, inspect, and chart every field in 3D or on the map, compare up to six scenarios with difference maps, and export the data.

956M
Cells in one city mesh — solved, not approximated
119k
Buildings simulated in a single model
16 days
Street-level heat forecast horizon
GPU
Whole-city physics in hours, on one cloud GPU

What partners say

Field-tested with the people shaping cities.

Greater Boston · Climate planning
“PGL's CityDigitalTwin provides an accessible way for urban planners to understand development options in terms of microclimate effects.”
John Bolduc · Climate Planner, Greater Boston
New York · The High Line · WXY
“We collaborated with Planète GreenLeaves on a thermal comfort and microclimate analysis to see how a proposed development project would affect the planted public spaces on New York's High Line. Their team brought deep technical expertise, responsiveness, and a strong commitment to quality. The insights they provided through detailed simulations were valuable in helping us assess climate-responsive design strategies. It was a pleasure working with them.”
Claire Weisz, FAIA, Hon. FRAIC, Hon. ASLA · Founding Principal, WXY

Working with

Trusted by teams shaping cities worldwide.

Clients & pilots
WXY Ramboll Tian Building Engineering Hydro-Québec
Universities & research
Arizona State University KAUST University of Sydney Florida Tech
Partners
UrbanSim Dynamic Hunter College
Backed by
NVIDIA Inception AWS Activate District3 Cleantech Open PME MTL V1 Studio

Book a demo

Design the climate-smart city.

See CityDigitalTwin run on your own site or district. We'll walk you through microclimate, energy, and grid results in 30 minutes.