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SunnyDays

ERA5 almanac — 8 years of real data

Boundary Waters in July

Boundary Waters in July: 42% of days see measurable rain, 78°F average high, 31% of days historically clear (n=248, ERA5 2018–2025).

Boundary Waters in July is historically a poor month for sun: only 31% of days clear across 8 years (n=248, avg high 78°F). Historical average, not a forecast.

What you are reading: 8-year historical averages from the ERA5 reanalysis, not a forecast. A month that is historically 90% clear can still be overcast on your specific trip. For this week’s actual forecast, see the live Boundary Waters page. Both can be true at once: “historically strong in this month; this particular week is not.” We label which is which.

Early vs. Late July

Clear-sky percentage for Boundary Waters in July, split by half-month. “n” is the number of days sampled across 8 years (2018–2025).
Period % Clear days Sample (n) Avg high
Early July
1st–15th		 35% n=120 78°F
Late July
16th–end		 27% n=128 78°F
Full month average 31% n=248 78°F

Sunshine & warmth in July

A second measure using actual sunshine hours (ERA5 sunshine_duration), not the daily weather code. A Lowcountry day with 12 hours of sun and a 25-minute afternoon storm is counted below as a warm, sunny day — because it was. How we define this.

Sunshine-based metrics for Boundary Waters in July. Primary: % of days ≥ 72°F with > 6 h of sunshine.
Period Warm & sunny (≥72°F, >6 h sun) Sample (n)
Early July
1st–15th		 88% n=120
Late July
16th–end		 77% n=128
Full month average 82% n=248
13.6 h median sunshine per day 93% of days exceed 8 h sunshine 42% of days see ≥ 1 mm rain — rain is not hidden
Comparison (old vs new): WMO-code “clear” bar: 31%. Sunshine-based “warm & sunny”: 82%. The 51-point gap is from brief afternoon convective storms that stamp the whole day as “rain” in the WMO code but leave the bulk of the sunshine untouched.

Bottom line

Boundary Waters is mostly overcast in July historically: only 31% of days are clear across 8 years (n=248), avg high 78°F. Most visitors this month will see more clouds than sun.

Every month in Boundary Waters

Compare across all months with data. Numbers are historical clear-sky %.

Historical clear-sky % for Boundary Waters, all months, ERA5 2018–2025.
Month % Clear Sample (n)
January 0% n=248 All destinations →
February 0% n=226 All destinations →
March 0% n=248 All destinations →
April 0% n=240 All destinations →
May 10% n=248 All destinations →
June 26% n=240 All destinations →
July ← this page 31% n=248 All destinations →
August 30% n=248 All destinations →
September 20% n=240 All destinations →
October 2% n=248 All destinations →
November 0% n=240 All destinations →
December 0% n=248 All destinations →

Frequently asked

Does it rain in Boundary Waters in July?

Sometimes. Boundary Waters sees measurable rain on 42% of days in July historically (n=248 days, ERA5 2018–2025) — not frequent enough to plan around, but not negligible either.

Is Boundary Waters good for sun in July?

It's mixed. Boundary Waters in July is clear on 31% of days historically (avg high 78°F, n=248 days, ERA5 2018–2025) — the outcome varies year to year.

How Boundary Waters compares in July

Head-to-head clear-sky comparisons against destinations travelers plausibly weigh against Boundary Waters this month — same passport tier, similar flight distance, both sides from the same 8-year ERA5 record.

All percentages are historical averages from the ERA5 reanalysis via Open-Meteo, 8 full years (2018–2025). “Clear” means avg high ≥ 72 °F, precipitation < 1 mm, and a non-precipitation weather code. This is history, not a forecast. The live 7-day outlook for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.