The cheapest hour of the day in Spain is not the same in February as in July. In winter, electricity is cheap at pre-dawn (windy nights, no demand). In summer, the sweet spot moves to midday (when solar floods the grid).
Knowing the seasonal pattern lets you schedule your washing machine, water heater, and life without obsessively checking prices every day.
The annual pattern
Here's where the cheapest window typically sits, based on five years of PVPC history:
| Month | Main cheap window | Expensive window |
|---|---|---|
| January | 02:00 – 05:00 | 19:00 – 21:00 |
| February | 02:00 – 05:00 | 19:00 – 21:00 |
| March | 03:00 – 05:00 + 13:00 – 15:00 | 20:00 – 22:00 |
| April | 13:00 – 16:00 | 20:00 – 22:00 |
| May | 12:00 – 17:00 | 21:00 – 23:00 |
| June | 12:00 – 17:00 | 21:00 – 23:00 |
| July | 12:00 – 17:00 | 21:00 – 23:00 |
| August | 13:00 – 17:00 | 21:00 – 23:00 |
| September | 13:00 – 17:00 | 21:00 – 23:00 |
| October | 03:00 – 05:00 + 14:00 – 16:00 | 20:00 – 22:00 |
| November | 02:00 – 05:00 | 19:00 – 21:00 |
| December | 02:00 – 05:00 | 18:00 – 21:00 |
It's a map, not GPS. The exact hour can shift 1–2 hours based on a specific day's weather. But the seasonal pattern is rock-solid.
Why it changes with the season
Two generators set the rhythm of Spanish prices:
- Wind — most active in winter and at night. Pulls prices down between 02:00 and 06:00 when there's wind.
- Solar PV — dominates from spring through autumn, especially 12:00–16:00. When there's sun, midday can drop to overnight-level prices.
Demand also shifts:
- Winter: peak demand is in the evening (heating, lighting, cooking).
- Summer: peak shifts to 21:00–23:00 (A/C running while it's still 30°C outside, just after people get home).
Result: in winter the expensive window is early evening (19:00). In summer it shifts to late evening (22:00).
The two transition months
March and October are special because they have two cheap windows:
Why two windows?
In March, there's still strong overnight wind and the midday sun is starting to deliver. In October, sun is fading but wind is returning. Both give you flexibility:
- Afternoons when you have laundry to do → start the washing machine at 14:00, ready at 16:00 when you get back from errands.
- Households with night-time routines → the classic 04:00 schedule still works.
April–September: the "electric lunch hour"
For half the year, the cheapest hour is at midday. This changes the optimization logic:
- A ceramic hob running at 14:00 can cost about the same per kWh as the fridge running at night.
- The electric water heater should be scheduled for 13:00–16:00, not pre-dawn.
- Laundry at 14:00 is as cheap as 04:00 — and you can pull it out at 16:00 without it sitting wet.
This surprises a lot of people who keep scheduling everything "for overnight" without realizing summer midday is just as cheap or cheaper.
Exceptions and events
A few events break the pattern:
- Cold snaps with high pressure (low wind + high demand) → prices stay elevated all day, no clear cheap window.
- Windy winter weekends → entire days at off-peak rates. Schedule big jobs.
- Sunny spring Sundays → some hours at zero or even negative wholesale prices. The "energy" portion of your bill might cost just a few cents.
The practical takeaway
Don't memorize every window. Two mental rules suffice:
- If it's cold (Nov–Mar) → schedule everything between 02:00 and 05:00.
- If it's hot (Apr–Sep) → schedule everything between 13:00 and 16:00.
In transition months (March, October), pick whichever fits your routine best.
For the specific day in front of you, check the 24-hour heatmap on the homepage — cheapest hour today and (after 20:15) tomorrow.