St Thomas solar guide

Strong coastal output, with a steep mountain-to-sea gradient.

St Thomas combines a productive southern coastal belt with much lower cells on the Blue Mountain slopes. A single parish average cannot describe both settings.

Local data guide · published 31 August 2026

Try a system size

What would that mean on a roof?

These figures estimate electricity from the panels, not money saved. A kWh is one unit of electricity on your bill; kW describes the panel system’s rated size. Your savings depend on when you use that electricity, whether you store it in a battery and whether you send any to JPS Jamaica.

Typical year

7,926 kWhabout 660 kWh per month on average

Middle half of locations

7,626–8,277 kWhDifferences between locations; your roof can change the result

Strongest month

March · 725 kWhLong-term average, not a forecast

Weakest month

November · 598 kWhAbout 17% below March

Colour map of modelled annual solar electricity output across St Thomas. — **Annual solar electricity across St Thomas**Each square is approximately 1 km. The stepped edge shows the source resolution rather than pretending the estimate is more precise.

About 1,350About 1,740 kWh/kWp

The parish is not one number

The coast leads. Northern mountain slopes create the lower tail.

The strongest modelled output runs along the southern side around Yallahs, Morant Bay and the coastal plain. It drops toward the higher northern terrain and deeply cut valleys.

The middle half of cells still spans a meaningful range, so hillside shade and roof exposure should be reflected in the installer’s forecast.

Cells analysed: 891
Central geographic range: 1,525–1,655
Typical variation: About ±4%

Month by month

How does solar output change through the year?

March is strongest in the long-term model. November produces about 83% of that output, so the annual figure should not be treated as twelve identical months.

634Jan

628Feb

725Mar

695Apr

662May

638Jun

711Jul

703Aug

686Sep

642Oct

598Nov

603Dec

Estimated monthly generation in kWh for the selected system size. Hover, tap or focus a bar for its detailed value. The figures are long-term estimates, not a weather forecast.

View the monthly figures as a table

Month	Per installed kW	5 kW system
January	126.7 kWh	634 kWh
February	125.6 kWh	628 kWh
March	145.0 kWh	725 kWh
April	139.0 kWh	695 kWh
May	132.4 kWh	662 kWh
June	127.6 kWh	638 kWh
July	142.2 kWh	711 kWh
August	140.6 kWh	703 kWh
September	137.3 kWh	686 kWh
October	128.4 kWh	642 kWh
November	119.7 kWh	598 kWh
December	120.6 kWh	603 kWh

Before asking for quotes

Questions worth asking in St Thomas.

Do mountains block morning or afternoon sun?Valley and hillside properties need a measured solar window. Parish-level annual data cannot see the local horizon.
Is the roof exposed to hurricane winds?Coastal and elevated sites can both be highly exposed. Require a mounting layout tied to the actual roof structure and waterproofing method.
Does salt exposure change the hardware?Near the coast, check the complete materials list, outdoor enclosure ratings and manufacturer warranty exclusions.
Can the installer support a remote site?Confirm monitoring, service call-outs and replacement-part arrangements before choosing equipment that only one supplier can maintain.

Use the Jamaica panel and roof guide to test the mounting and equipment answers in a quotation.

Generation is not the bill

A 5 kW system making 660 kWh a month will not automatically erase the same-sized bill.

Timing decides value

Solar used in the home avoids the retail cost of a JPS Jamaica unit. Surplus sent through net billing receives a much lower export credit.

A battery moves energy

A battery can carry daytime generation into evening use and provide outage cover, but it does not make the panels generate more.

Your roof changes the result

Shade, direction, heat, dirt, cable losses and equipment choices move a real installation away from the parish benchmark. Use the panel guide to test those roof assumptions.

How we calculated this

Where do these estimates come from?

We use long-term sunshine data to estimate panel output across the parish. These are planning averages, not a forecast for your roof. Shade, roof direction and equipment can change the result.

See the data, calculation and source assumptions

We selected the 891 Global Solar Atlas PVOUT grid cells whose centres fall inside the St Thomas parish boundary, then calculated the annual mean, central 50% range and monthly means.

The source models a free-standing crystalline-silicon system at optimum fixed tilt. It is useful for parish comparison and early planning, not a guarantee for a particular roof.

Solar source: Global Solar Atlas 2.0 PVOUT
Source years: 1999–2018 long-term average
Spatial resolution: 30 arc-seconds, approximately 1 km
Calculation: Jamaica Solar Check parish aggregation

Solar data obtained from Global Solar Atlas 2.0, developed and operated by Solargis on behalf of the World Bank Group with ESMAP funding. Source data © 2019 Solargis, CC BY 4.0. Parish calculations and colour map are adaptations by Jamaica Solar Check; the source organisations do not endorse this site. Boundary geometry: geoBoundaries JAM ADM1, sourced from OpenStreetMap/Wambacher, CC BY-SA 2.0.