The short answer
Lock during shoulder seasons before futures price the winter peak.
Wholesale electricity futures front-load the winter spike. The cleanest lock-in window for most deregulated zones runs August through October — far enough ahead of the December-to-February ramp that the spike is not yet priced into a 24-month curve, but close enough that suppliers compete hard for the next-quarter delivery year. This guide walks through the seasonal pattern, the exceptions, and how the timing question changes for residential vs commercial accounts.
Why August through October consistently prices cheapest
Suppliers price fixed-rate offers off the wholesale futures curve plus a hedging margin. The futures curve front-loads the winter risk because gas-for-heat demand and capacity tightness drive a recurring December–February peak in PJM and ERCOT zones.
In the August-to-October window the next-winter peak is not yet priced aggressively into a 24-month curve. Suppliers also have most of their next-year delivery capacity to place, and they compete hard for clean books. The combination produces the cheapest priced offers of the year for the same contract structure.
For commercial multi-site bundles, September is historically the cheapest single month to clear an RFP. For residential, the window is wider — late August through mid-November is usually competitive.
Infographic
PJM capacity auction clearing prices — the silent compounder
When the window inverts — and when not to wait
There are three exceptions to the seasonal pattern. The first is when wholesale prices have spiked dramatically due to a one-time event (a generation outage, a regulatory ruling), and supplier inventories are heavy. In that scenario the lock window can briefly invert — locking immediately after a spike beats waiting for the seasonal pattern.
The second exception is when an existing contract is expiring inside a known seasonal window. The renewal trap (rolling silently into a variable default) is more expensive than locking even at a slightly off-cycle rate.
The third exception is when a multi-state portfolio bundle has expiry dates spread across the calendar year. Synchronising the expiry to a single seasonal window is sometimes worth a small early-termination cost on one or two sites.
- Lock during August–October if you have flexibility on timing.
- Lock immediately if your contract is within 60 days of expiry.
- Avoid renewing in January–February — winter spike is already priced in.
- For commercial portfolios, synchronise expiry dates to September if possible.
How to read the futures curve like a supplier
Suppliers price off NYMEX natural gas and ICE electricity futures plus regional basis. The numbers move daily. Two heuristics get most of the value without reading the screens daily: the contango/backwardation shape, and the seasonal spread.
Contango (later months priced higher than near months) is the normal shape and signals locking longer pays a premium for the certainty. Backwardation (later months cheaper than near months) is unusual — when it happens, locking longer is the steal of the year.
The seasonal spread (Dec–Feb minus Aug–Oct) is also informative. A wider spread signals more winter risk priced in; a narrower spread signals the market expects a milder winter or more available capacity.
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