Octopus Greener Nights (Greener Days Forecast)

Octopus Greener Nights (formerly Greener Days)

Octopus Greener Nights (formerly Greener Days) is a free overnight forecast (23:00–06:00) showing when the UK grid is greenest. It helps Intelligent Octopus Go customers plan EV charging, earn Octopoints, and cut their carbon footprint.

In September 2025, Octopus Energy rebranded their popular Greener Days forecast to Greener Nights, a name that finally matches the time window the raw API data has always covered.

💡 New for September 2025: Customers on the Intelligent Octopus Go tariff can earn up to ~£42/year in Octopoints by charging mainly on greener nights.

Returning visitors to this page and to the daily graphs I post will know I always said this scheme should have been called Greener Nights, not Greener Days. I’m glad Octopus made the change because the new name finally matches the time window the raw API data has always covered.

If you knew Greener Days, this is the same service, just renamed to reflect its real focus on overnight charging when the grid is at its cleanest.

Table of Contents

This article about Greener Days is a comprehensive read, drawing on both data and hands-on testing.

Use the Table of Contents below to jump straight to the questions that matter most — or scroll through at your own pace.

 What is Octopus Greener Nights?

Greener Nights is a free forecast showing the overnight periods when renewable electricity is most abundant.

Each night is given a Greenness Score (0–100), based on predicted renewable generation. Extra-green nights are highlighted with a crown icon in your Octopus account, making it easy to spot the best times to plug in.

From September 2025, Octopus also introduced Octopoints rewards for Intelligent Octopus Go tariff customers:

• ✅ 70% of your monthly charging on greener nights → 320 Octopoints

• ✅ 80% of your monthly charging on greener nights → 640 Octopoints

• ✅ 90% of your monthly charging on greener nights → 2800 Octopoints

These points can be redeemed against your energy bill, Octopus Store products, or even donated to charity.

In short: Greener Nights gives you a clear signal of when the UK grid is at its cleanest, and rewards you for charging your EV when it helps most.

Thinking about switching energy suppliers?

Homeowners who join Octopus Energy using my referral link get £50 free credit after signing up.  Thank you if you do so.

How the Greener Nights forecast works

The Octopus Greener Nights forecast is built using National Grid data and renewable generation predictions. It looks up to 15 days ahead, with today and tomorrow’s forecasts being the most accurate — just like a weather forecast.

Octopus analyse:

• Wind generation forecasts (the biggest factor in UK renewables)

• Other renewable sources such as solar and hydro

• Grid carbon intensity – how clean or dirty the mix is expected to be

Each overnight period (23:00–06:00) is then given a set of values:

• Greenness Score (0–100) → higher means cleaner energy

• Highlight flag → marks the greenest nights in your account with a crown icon

• Index ranking → orders the nights from greenest to least green

For example: a score of 90/100 could indicate strong offshore wind generation and minimal fossil fuel backup — the perfect time to charge your EV or run appliances.

Developer tip: the raw data is available via Octopus’s GraphQL API for anyone who wants to dig deeper.

 Greener Nights Forecast

Although the scheme was originally called Greener Days, the forecast has always focused on overnight hours. The rebrand to Greener Nights makes this clearer: the green window runs from 11PM to 6AM.

During these hours, the UK grid often relies more heavily on wind power and less on fossil fuels. That means your EV charging, appliances, or battery top-ups have a much lower carbon footprint if you run them overnight.

On Energy Stats UK, we continue to present the forecast window as 00:00–06:00 to simplify comparisons across tariffs and other data.

Today’s Greener Nights forecast

We post the latest Greener Nights graph to our social media accounts (Twitter / X, Bluesky or Mastodon) daily — alongside Agile Tariff, Tracker Tariff and Outgoing Octopus Export charts.

This makes it easy to see at a glance which overnight periods are cleanest for EV charging, appliances, or battery top-ups.

Why my Greener Nights charts differ from the Octopus site

You might notice that my Greener Nights bar charts don’t always line up exactly with the indicators shown on the Octopus website.

Here’s why:

• Underlying data → The raw API covers the period 11PM to 6AM.

• Octopus approach → They tag the greener night based on when the period starts (23:00). For example, a forecast from Sun 14th 11PM → Mon 15th 6AM is marked as Sunday.

• My approach → I plot the greener night based on the bulk of the time window (00:00–06:00), and call that Monday.

This way, my charts are consistent with other tariff data (like Agile) and easier to compare across datasets.

Which version is correct?

Both are valid — it just depends on which source you prefer:

• Octopus website → If it highlights green on Sunday, it means plug in Sunday evening.

• My charts (and daily posts) → If you see a green score for Monday, that covers 00:00–06:00 Monday — so again, plug in Sunday evening.

I stick with the 00:00–06:00 standard because it makes comparisons cleaner, but whichever method you choose, just be consistent.

Side-by-Side Example

Let’s look at a comparison from the same day to highlight the differences clearly:

• My chart (Left) → show the same greener night as Monday (00:00–06:00)

• Octopus website (Right) → shows the greener night as Sunday

Greener Nights rewards and Octopoints

From September 2025, Octopus added Octopoints rewards to the Greener Nights scheme. To be eligible, you’ll need to be on Intelligent Octopus Go, have a connected smart meter (half-hourly readings), and not be part of PowerUps, then sign up through your Octopus account.

If you qualify, you’ll be rewarded for doing most of your charging when the forecast shows greener nights.

Monthly Greener Nights rewards

At the start of each month, Octopus reviews your charging data and awards points based on how much you aligned with the greener window (11PM–6AM):

• ✅ 70% of charging on greener nights → 320 Octopoints (~40p)

• ✅ 80% of charging on greener nights → 640 Octopoints (~80p)

• ✅ 90% of charging on greener nights → 2800 Octopoints (~£3.50)

(800 Octopoints = £1 credit)

How to use Octopoints

• Use them to reduce your Octopus energy bill

• Spend them in the Octopus Store on gadgets, EV gear, or energy tech

• Donate them to good causes

Annual Octopoints potential

If you consistently hit the top reward tier (90% = 2800 Octopoints/month), that adds up to:

• ~33,600 Octopoints per year

• Worth about £42 off your bill (or to spend / donate)

Lower tiers add up too:

While the financial value is modest, the bigger benefit is reducing emissions, supporting the grid, and knowing you’re helping accelerate the transition away from fossil fuels.

How to make Greener Nights work for you

The Greener Nights forecast is most useful when you turn it into action. A few simple habits can help you make the most of the greenest hours:

• Check the forecast in your Octopus account, here on Energy Stats UK website of our social media feeds.

• Plan your charging so your EV tops up on the highest-scoring nights.

• Shift appliances (washing machine, dishwasher, battery storage) to run overnight.

• Collect rewards — if you’re on Intelligent Octopus, doing the majority of your charging on greener nights earns you Octopoints.

Even if you’re not on a tariff with direct price savings, shifting usage into greener windows helps lower carbon emissions and supports a cleaner energy grid.

When Greener Nights are cheaper too

On some tariffs, the cleanest nights also line up with the cheapest prices.

That’s because when the grid is flooded with wind power, wholesale prices can drop — sometimes even going negative.

• Agile Octopus → greener nights often mean lower unit rates, and occasionally you’ll even get paid to use power.

• Intelligent Octopus Go → prices don’t change overnight, but you can collect Octopoints rewards by charging during greener nights.

• Other smart tariffs (like Tracker, Go, Cosy, or Flux) → the pricing varies, but the environmental benefit remains the same.

That means timing your usage for greener nights can deliver a double win:

• Lower your carbon footprint

• Pay less (or get rewarded) for shifting usage when the grid is at its cleanest

Pricing for other Octopus Time of Use / Smart Tariffs can be found here: Agile, Cosy, Go, Flux, Intelligent Go, and Tracker.

Where Greener Nights data comes from

The Greener Nights forecast is powered directly by Octopus Energy’s systems, which draw on:

• National Grid data

• Renewable generation forecasts (primarily wind, plus solar and hydro)

• Carbon intensity predictions for each overnight window

Behind the scenes, this data is made available through the Octopus GraphQL API, which exposes values for each forecasted period:

• validFrom / validTo – the time window (always 23:00–06:00)
• greennessScore – a 0–100 score for how clean the energy mix is
• greennessIndex – relative ranking of nights, greenest to least green
• highlightFlag – crown icon marker for especially green nights

👉 Example:

A forecast with a 90/100 greenness score usually means high offshore wind generation, low fossil fuel backup, and the ideal time to charge or shift usage.

Developer tip: you can experiment with this data yourself via Octopus’s public GraphQL endpoint:

https://api.octopus.energy/v1/graphql/#query=query%20GreennessForecast%20%7B%0A%20%20greennessForecast%20%7B%0A%20%20%20%20validFrom%0A%20%20%20%20validTo%0A%20%20%20%20greennessScore%0A%20%20%20%20greennessIndex%0A%20%20%20%20highlightFlag%0A%20%20%7D%0A%7D&operationName=GreennessForecast

You can see in this screen snippet how the data is presented.

Greener Nights score (next 5 days)

Greener Nights vs Agile and Tracker (last 50 days)

Note: I’ve reversed the scale on the graph for the Greener Nights Score to be a negative value to scale better with the lower Agile and Tracker pricing (right hand side)

The Greener Score still shows positive within the graph though.

Where to check the Greener Nights forecast

You can view the Greener Nights forecast in several places:

• Octopus Energy account → shows your personal forecast with crown icons on the greenest nights.

• Energy Stats UK → daily Greener Nights charts shared here and on social media (Twitter / X, Bluesky, Mastodon).

• Octopus GraphQL API → for developers who want to access raw forecast data.

How to sign up for Greener Nights and who’s eligible

Joining Greener Nights is simple, but you’ll need to meet a few requirements first:

• Have a smart meter that sends half-hourly readings to Octopus

• Be on Intelligent Octopus Go (IOG)

• Not be enrolled in PowerUps (another Octopus flexibility scheme)

If you qualify, you can sign up by logging into your Octopus Energy account and visiting the official page here:

👉 octopus.energy/smart/greener-nights

Once registered, your Greener Nights forecast will appear in your account within a few days, and you’ll start earning Octopoints rewards for charging during greener nights.

Final thoughts on Greener Nights

Whether you knew it as Greener Days or now as Greener Nights, the idea remains simple: shift your usage to the greenest hours and everyone benefits.

By checking the overnight forecast and planning EV charging or appliances accordingly, you can:

• Lower your carbon footprint

• Help the grid make better use of renewable wind power

• Save money on flexible tariffs like Agile or Tracker

• Earn Octopoints rewards on Intelligent Octopus Go for charging at the greenest times

It’s a rare win-win: better for the environment, supportive of the UK’s energy transition, and often better for your wallet too.

If you’re not yet with Octopus, switching gives you access to Greener Nights — plus you can start with £50 free credit via my referral link.  Thank you if you decide to use that.

FAQs About Octopus Greener Days

What happened to Octopus Greener Days?

Octopus Greener Days has been renamed Octopus Greener Nights. The scheme always focused on overnight hours, and the new name reflects that more accurately.

What is Octopus Greener Nights?

Greener Nights is a free forecast for Octopus Energy customers on the Intelligent Octopus Go tariff. It shows which nights (11PM–6AM) are greenest, based on wind generation and grid carbon intensity.

How do rewards work with Greener Nights?

If you’re on the Intelligent Octopus Go tariff, you can earn Octopoints by charging your EV during greener nights:

• 70% of charging on greener nights → 320 Octopoints

• 80% of charging on greener nights → 640 Octopoints

• 90% of charging on greener nights → 2800 Octopoints

Do I need a specific tariff?

Yes. Greener Nights rewards are only available on the Intelligent Octopus Go tariff.

How far ahead can I see the forecast?

You can view up to six days ahead, with updates every day. The forecast is most accurate for today and tomorrow and becomes less reliable beyond that, similar to a weather forecast.

Can I get notifications?

Octopus doesn’t send notifications directly, but Energy Stats UK and other third-party apps can send alerts when the grid is greenest. You can follow daily updates on Twitter / X, Bluesky, or Mastodon.

Why was it called Greener Days if it’s at night?

It started as a marketing choice. Since the forecast always covered overnight hours, Octopus rebranded it in 2025 to Greener Nights, a name that fits its true purpose.

When did Greener Days become Greener Nights?

Octopus Energy made the change in September 2025, aligning the name with the overnight charging window (11PM–6AM).

Who can sign up for Greener Nights?

Greener Nights is open to Intelligent Octopus Go customers with a smart meter that sends half-hourly readings. You can’t join if you’re already part of the PowerUps scheme.

How do I sign up for Greener Nights?

Log in to your Octopus Energy account and visit the Greener Nights page. If you’re on the Intelligent Octopus Go tariff and have half-hourly readings enabled, you can register in a few clicks. Your forecast will appear in your account within a few days.