Warm enough to swim? Springfield month by month
| Month | Daily high | Daily average | Verdict |
|---|---|---|---|
| January | 35°F | 25°F | Off-season |
| February | 38°F | 28°F | Off-season |
| March | 47°F | 36°F | Off-season |
| April | 60°F | 48°F | Off-season |
| May | 72°F | 59°F | Heater territory |
| June | 80°F | 67°F | Brisk — fine in a warm spell |
| July | 85°F | 73°F | Comfortable |
| August | 83°F | 71°F | Comfortable |
| September | 75°F | 63°F | Brisk — fine in a warm spell |
| October | 63°F | 51°F | Heater territory |
| November | 51°F | 41°F | Off-season |
| December | 40°F | 31°F | Off-season |
Verdicts follow the daily average: 68°F+ is comfortable for most people, 75°F+ is prime, and below 62°F you're in heater territory. An unheated pool's water tends to sit near the recent daily average, a touch above it in spring and below in fall.
Reading the Springfield pool year
The Springfield season splits into three acts. Opening (May 27 – Jun 18): clear the cover, rebalance, and shock — our dosing calculator turns your first test kit reading into exact amounts. Midseason: weekly testing and small corrections, with chlorine demand peaking around July. Closing (Aug 27 – Sep 18): wait for water to hold below ~60°F, balance, then cover — algae is nearly dormant by then, which is what makes spring easy. With only ~93 unheated days, a heater earns its keep faster in Springfield than almost anywhere — size one honestly with the heater calculator before the season slips by.
Frequently asked questions
When should I open my pool in Springfield?
Most Springfield owners are happy opening in the May 27 – Jun 18 stretch — that's when daily average air temperature climbs through the low-to-mid 60s°F, which puts the water near 70°F within a couple of weeks. Opening earlier is fine (algae actually prefers a late opening: a warm, covered pool with no chlorine is a petri dish); swimming just starts brisk.
When should I close my pool in Springfield?
Around Aug 27 – Sep 18, as daily averages fall back through the low 60s°F. Waiting until water holds below ~60°F is smart — algae is nearly dormant there, so the pool goes into winter clean. Closing too early in warm weather is the classic recipe for a swampy spring opening.
How long is the swim season in Springfield?
About 93 days without a heater — from roughly Jun 6 to Sep 8. A heat pump or gas heater typically adds 3–6 weeks on each end; a solar cover alone adds a week or two by holding overnight gains.
Where do these Springfield dates come from?
From 1991–2020 NOAA temperature records at the Westfield Barnes Municipal Airport station, 12 km from central Springfield. The working assumption: pools become pleasant as daily average air temperature passes 62–68°F, since water lags air by a week or two. A heater, cover, screened enclosure, or an unusually sunny yard all shift the real dates.