Summer can be a double-edged sword for small businesses. While tourists swell footfall for some, others — particularly B2B service providers and seasonal retailers — see revenue thin out. Over the years I’ve helped clients survive (and sometimes thrive) through slow months by building cashflow forecasts that are realistic, flexible and actually used. Here’s the practical, no-nonsense approach I use and teach so you can build a forecast that survives a slow summer month.
Start with what you actually have: a clean opening cash balance
The most common forecasting mistake I see is starting with a guessed bank balance. Before you forecast, get your opening cash position right. Pull your latest bank statement and reconcile it to your bookkeeping. If you use Xero, QuickBooks or FreeAgent, run the bank reconciliation — don’t rely on the balance your bank feed shows until you’ve cleared outstanding items.
Make sure to include:
Project conservatively on income
When summer is slow, optimistic revenue forecasts are the fastest way to create a shortfall. I encourage clients to build two revenue scenarios into their forecast:
Use your bookkeeping to break down revenue by client, product and channel. Some streams are predictable (like retainers) and can be treated as near-cash, while one-off sales or late-paying clients should be discounted or time-lagged in your cashflow.
Map timing, not just amounts
Cashflow is about timing. A sale booked in July might not translate into cash until August—or September—depending on invoice terms and customer behaviour.
When I build forecasts I add columns for:
If you invoice monthly on the 1st with 30-day terms, expect most payments around the 1st–10th of the following month. For clients who regularly pay late, shift projections to reflect their actual payment habits.
List every outgoing — and be brutally honest
It’s tempting to only include big visible costs like rent and salaries, but small regular payments add up. When I help clients model a slow period we make sure to include:
Use your past 6–12 months of bank statements and a supplier master list to avoid missing recurring payments. For lump-sum expenses like insurance, spread them across months in the forecast or show them clearly when they fall due.
Build an actionable forecast template
I usually construct a simple month-by-month table for the next 6 months. Keep it simple enough to update weekly but detailed enough to make decisions. Here’s an example layout you can copy into a spreadsheet:
| Month | Opening Cash | Expected Receipts | Expected Payments | Net Cash Flow | Closing Cash |
|---|---|---|---|---|---|
| June | £12,500 | £9,000 | £15,000 | -£6,000 | £6,500 |
| July | £6,500 | £6,000 | £10,000 | -£4,000 | £2,500 |
| August | £2,500 | £5,000 | £9,000 | -£4,000 | -£1,500 |
That table gives you an immediate visual of where you go negative and when you’d need to act. I also add a column for "actions" where I track mitigating steps (e.g., chase client A, delay supplier payment, draw on overdraft).
Plan and prioritise responses
A forecast is only useful if it triggers actions. For each month that shows risk I map specific, ranked interventions:
Review and update weekly
Cashflow is dynamic. I run a quick weekly review with clients during slow months: update actuals, check for late payments, confirm supplier negotiations and revise the forecast. That weekly habit often prevents surprises and keeps decision-making calm and deliberate rather than reactive.
Use tools that save time and surface risks
Cloud accounting platforms like Xero, FreeAgent and QuickBooks all have simple cashflow reporting tools that can automate parts of this work. For more advanced needs, I use forecasting add-ons such as Float or Pulse that sync with bookkeeping and let you model scenarios quickly. If you prefer spreadsheets, set up formulas for rolling sums and conditional formatting so negative balances stand out.
Finally, communicate with stakeholders early. If you have a landlord, supplier or lender, a transparent conversation with a sensible plan is almost always better than silence. I’ve seen landlords accept short-term reduced rent with a small top-up later when presented with a straightforward forecast.
Building a cashflow forecast that survives a slow summer month isn’t about predicting the future perfectly — it’s about giving you early warning and practical options so you can steer rather than react. With a clean opening balance, conservative income assumptions, realistic timings, and weekly updates, you’ll be in a much stronger position to keep the business steady through the heatwave and back into growth when autumn arrives.
