The heat is at a record
The variable this series opened with is the one the year turns on. Global surface temperature reached its highest value in the instrumental record in 2024, at 1.28 degrees above the mid-twentieth-century baseline, capping a two-decade climb; 2025 stepped back slightly to 1.19 degrees as a weak La Nina cooled the Pacific, but remained among the warmest years ever measured. For a solar panel this is not an abstraction. The heat penalty of part 01, the output a module gives up simply for running hot, is a direct function of this temperature, and it now sits at its structural maximum: an average operating cell temperature near 53 degrees and a static loss of most of a tenth of nameplate output before the smaller, slower warming drift is even counted.
| Year | Anomaly °C | ENSO state | Global precip mm |
|---|---|---|---|
| 2021 | +0.85 | La Nina, moderate | 1007 |
| 2022 | +0.90 | La Nina, strong | 1008 |
| 2023 | +1.17 | El Nino, onset | 1022 |
| 2024 | +1.28 (record) | El Nino, weak | 1059 (record) |
| 2025 | +1.19 | La Nina, weak | 1019 |
NASA GISTEMP v4 temperature and GPCP precipitation, with the ENSO state from the NOAA Oceanic Nino Index. 2024 is the hottest and wettest year in the 2004-2025 record; the year-to-year swing between them is the variability of part 03, not a trend reversal.
Solar is scaling into it
The second half of the state of the climate is the electricity the world actually generates, because that is what decides how much the heat and the sky trends matter at scale. The transition crossed two thresholds in the current record. Total renewables reached 34 percent of global generation and drew level with coal at 33.6 percent, ending coal's long reign as the single largest source in all but name. And solar, which was a rounding error in 2004, reached 8.7 percent and overtook wind to become the largest single renewable source on the planet.
| Source | 2004 share | 2025 share |
|---|---|---|
| Coal | 40% | 33.6% |
| Renewables (total) | 18% | 34% |
| Solar | ~0% | 8.7% |
| Wind | 0.7% | 8.4% |
Ember Global Electricity Review; 2004 is a composite estimate (data_version composite_est), 2025 is Ember-native. Renewables total includes hydro. Solar overtook wind, and renewables drew level with coal, in the current record.
The two readings belong together. Every point of share that solar takes is a point of the world's electricity that now runs through the production climate this series maps: exposed to the heat penalty, the brightening and dimming, the variable years, the soiling and the smoke. Solar is no longer a niche whose climate sensitivity is a curiosity; it is a third of the way to being the backbone, and the environment it runs in is a first-order question for the grid, not just for the individual roof.
The nine readings
The series in one view. Each variable at its latest reading, and its direction of travel, with the full treatment a click away.
| Variable | Reading, 2026 | Direction |
|---|---|---|
| 01 · Heat penalty | 53°C mean cell temperature; 9.8% static loss (PERC); +0.34% added by year 25 of warming | Rising |
| 02 · Brightening and dimming | 26 of 40 markets brightening over two decades, 14 dimming; +0.4% on average | Mixed by region |
| 03 · The variable years | 2025 a weak La Nina after the 2023-24 El Nino; interannual swing 2.5% to 8% | Cyclic, no trend |
| 04 · Beam and diffuse | Diffuse share 19% (Atacama) to 63% (Reykjavik); sets where trackers pay | Structural |
| 05 · Rain, dust and soiling | 1.5% temperate to a 20% Gulf lower bound; drying markets lengthen the accumulation window | Stable, rising in dry belts |
| 06 · Smoke | A recurring seasonal factor in three regions; fire weather trending up where it reaches grids | Rising |
| 07 · Wind cooling | Refunds 3.6% to 6.9% of output; independent of temperature (r = -0.09) | Stable |
| 08 · Storms and extremes | Hail high-hazard in 2 markets, 5 exempt; hail-days rising in Sydney and Perth | Mixed, rising in parts |
| 09 · The compound trajectory | Value per kW $40 (Cairo) to $514 (Los Angeles); the tariff spread is 20 to 1 | Market-driven |
Each reading is the headline figure from that part of the series; follow the link for the full data, method and buyer guidance. Directions describe the physical or market trend, not a forecast.
What the 2026 state means
Read together, the nine readings settle one argument the series has made from the start. Of everything that moves the value of a solar kilowatt, the physical climate, the sum of parts 01 through 08, varies it by roughly a factor of two from the best market to the worst, while the market itself, the local price of power in part 09, varies it by a factor of twenty. The state of the solar climate in 2026 is therefore two states at once. The physical state is demanding and, in its slow terms, worsening: record heat, rising fire weather, lengthening dry spells in the markets that soil hardest. The market state is transforming and, for solar, favourable: the technology is now the largest renewable and climbing. A serious reader holds both. The heat and the storms decide which module and which mount; the sky trend and the variability decide which baseline to believe; and the tariff decides, more than any of them, whether the kilowatt is worth generating at all.
The one instruction that falls out of the whole series is to stop treating sunlight as the question. A solar system is a twenty-five-year instrument exposed to nine moving variables, and the sunniest place is neither the safest nor the most valuable. Reading the production climate, all of it, is the difference between a number on a brochure and a number you can bank.
Method and cadence
This is a synthesis, not a new measurement. Every figure is the current reading of a pillar published in full elsewhere in the series, drawn from the same public records: NASA for temperature, irradiance, wind and the reanalysis behind the yield model; NOAA and partner agencies for the ocean and circulation drivers; Ember for the generation mix; and published retail tariffs for the demand side. The temperature and mix figures are the latest complete-year values in the record at the time of writing, mid-2026, on the 2024 and 2025 data. This report is designed to be refreshed as each year's record lands: the structure holds, and the numbers move. Where a reading rests on a modelled or literature-derived figure rather than a direct measurement, that limit is stated in the underlying part. Nothing here is forecast; it is the record, read as of now.