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Oct 2026 / Outdoor thermal comfort

How do you keep a coastal precinct walkable in an Abu Dhabi August?

Saadiyat Island Residential Precinct, Exit 14, Abu Dhabi. A pedestrian-scale outdoor thermal comfort study that finds the critical summer day, maps where heat stress builds up, and tests three ways to cool the public realm.

54.1% less hotspot area on the summer peak day
with trees and shade structures

3D UTCI map of the precinct on 12 August, red to yellow, with the hotspot areas above 30 degrees outlined in green in the central open parcel, eastern edge and northern pocket — Baseline UTCI on 12 August, hotspots above 30 °C outlined

Project type: Residential precinct, outdoor public realm
Location: Saadiyat Island, Abu Dhabi, UAE
Critical day: 12 August, 06:00–22:00
Metrics: UTCI, MRT, thermal comfort percentage, hotspot area
Hotspot threshold: UTCI > 30 °C
Tools: Ladybug, Honeybee, EPW climate data

Overview

The precinct sits on the coast of Saadiyat Island, with low-rise residential blocks around large open parcels, landscaped streets and direct access to the beach. The study looked at the outdoor spaces people actually walk and sit in, at pedestrian height, to find what drives heat stress there and which design moves reduce it.

The challenge

In a hot-arid coastal climate, air temperature is only part of the story. Strong sun heats people and hard surfaces directly, and paving and façades re-radiate that heat for hours. The question was where on the site this radiant load makes outdoor spaces uncomfortable, and whether paving, façade colour or shade does the most to fix it.

Aerial 3D render of the precinct: white residential blocks, tree-lined streets and open parcels along the coast — Site model of the Saadiyat Island Residential Precinct

Finding the critical day

Four representative days covering winter, the transition seasons and the summer peak. 12 August shows the highest UTCI and became the design case for everything that follows.

Condition	Representative day	UTCI range	Reading
Winter	04 Feb	7.68–19.52 °C	Low UTCI, generally comfortable
Transition	22 Apr, 15 Oct	12.95–28.42 °C	Moderate rise, local warm pockets
Summer peak	12 Aug	21.22–31.36 °C	Highest stress, critical design case

Three UTCI plan maps of the precinct for winter, the transition seasons and the summer peak, from blue and purple in winter to orange and yellow in summer — UTCI for the winter, transition and summer peak days, 06:00–22:00

Summer peak baseline

On 12 August, mean UTCI across the site is 27.18 °C and the peak reaches 31.36 °C. The hottest spots cluster in the large central open parcel, along the eastern edge and in a northern pocket, where there is little shade and a lot of exposed hard surface.

Mean UTCI: 27.18 °C; Area-wide moderate heat stress. Peak 31.36 °C.
Mean MRT: 35.22 °C; Radiant exposure is a major part of the discomfort.
Peak MRT: 53.08 °C; High local solar and radiant load in exposed areas.
Hotspot area: 10,421 m²; Ground where UTCI exceeds 30 °C.
Summer comfort: 57.84%; Thermal comfort percentage. A large share stays outside comfort.

Three baseline plan maps of the precinct: UTCI in red and orange, mean radiant temperature in yellow and orange, and thermal comfort percentage in green and pink — Baseline UTCI, mean radiant temperature and thermal comfort percentage, 12 August

The MRT and UTCI maps follow each other closely. Mean radiant temperature combines direct, reflected and emitted radiation, so where people are exposed to sun and hot surfaces they feel much hotter than the air temperature suggests. That points to shade as the main lever, with surface treatments as support.

Three ways to cool the precinct

Each scenario targets a different part of the heat problem and was run on the same summer peak day.

Scenarios tested

01 Permeable asphaltPorous paving to reduce heat stored in the hardscape.

02 White façadesWhite-painted building façades to absorb less sun.

03 Trees + shade structuresStreet trees and lightweight canopies over routes, seating and open spaces to block direct sun.

Hotspot area

Area with UTCI above 30 °C, m², 12 August

Baseline

10,421

01 Permeable asphalt

7,786

02 White façades

10,337

03 Trees + shade

4,783

Trees and shade remove 5,638 m² of hotspot, a 54.1% reduction. Permeable asphalt removes 25.3%. White façades barely change it, at 0.8%.

Summer peak performance, 12 August
Scenario	Mean UTCI	Peak UTCI	Mean MRT	Peak MRT	Hotspot area	Hotspot change	Comfort
Baseline	27.18 °C	31.36 °C	35.22 °C	53.08 °C	10,420.80 m²	—	57.84%
01 Permeable asphalt	27.12 °C	31.20 °C	34.98 °C	52.58 °C	7,785.60 m²	−25.3%	58.35%
02 White façades	27.16 °C	31.29 °C	35.11 °C	52.86 °C	10,337.45 m²	−0.8%	58.02%
03 Trees + shade	26.57 °C	31.02 °C	33.19 °C	51.76 °C	4,783.20 m²	−54.1%	62.05%

Scenario 03 on the summer peak

With trees and shade structures, mean MRT drops by 2.03 °C and mean UTCI by 0.61 °C, and the thermal comfort percentage rises by 4.21 points, from 57.84% to 62.05%.

Three Scenario 03 maps of the precinct for UTCI, mean radiant temperature and thermal comfort percentage, with larger blue and green shaded areas than the baseline — Scenario 03 UTCI, mean radiant temperature and thermal comfort percentage, 12 August

Conclusion

Shade does the most. Trees and shade structures cut the summer hotspot area by more than half and give the best result on every indicator, so the recommended direction is to put them first across the persistent hotspots and the main pedestrian routes.

Permeable or cool paving is a useful second layer where large paved areas store heat. White façades on their own change little at street level. A combined strategy led by shade and vegetation, backed by targeted paving changes, is the clearest path to a more comfortable public realm.

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