July brings 25°C daytime highs, 18mm of precipitation across about 3 wet days and 14.3 hours of daylight — best for reliable sunshine. The strongest run of the year is June to August. December is the quietest month: cold and snow-focused, and still good for snow, cabin weekends and festive season.
Long-run climate normals for Mammoth. Month ratings compare months within Mammoth only — they are not a ranking of Mammoth against other destinations, and they are not a forecast for a specific year.
Conditions on this page are recalculated from the latest forecast every time it is opened, for the current date in the location's own time zone. Showing .
| Best month | July — Reliable sunshine |
| Best 3-month window | June–August |
| Quietest month | December — Cold and snow-focused |
| Driest month | July — 18mm |
| Wettest month | December — 90mm |
| Warmest / coolest | July 25°C / January 4°C |
| Seasonality | Strongly seasonal — the months feel like different places |
| Annual rainfall | 621mm over roughly 107 rain days |
December gets roughly 400% more precipitation than July — 90mm against 18mm. That difference, more than temperature, is what changes how a day here feels.
Mammoth swings 21°C between July (25°C) and January (4°C) — the month you pick changes what you pack more than where you go.
June gives you 14.6 hours of daylight against just 9.4 in December — a 5-hour difference in how much you can actually fit into a day.
July is the driest month at 18mm across roughly 3 wet days, while December peaks at 90mm — which falls as snow at those temperatures, so the figure is water equivalent.
January–December sit at or below freezing, so the precipitation shown for those months falls mainly as snow rather than rain — the millimetre figures are water equivalent, not puddles.
August is almost as good as July, but usually quieter and cheaper. If your dates are flexible, it is the easier trip.
Mammoth changes character completely through the year — July and December are effectively two different destinations. Pick the month that matches what you want to do, not the highest-rated one.
Ratings compare months within Mammoth, not against destinations worldwide: five stars means the best time to be here, not that Mammoth beats anywhere else. Tags describe what the conditions actually suit.
| Month | Rating | High / Low | Precipitation | Wet days | Sun | Daylight | Best for |
|---|---|---|---|---|---|---|---|
| January | ★★☆☆☆ | 4°C / -9°C | 63mm (snow) | 14 | 3h | 9.7h | Snow · Cabin weekends · Low-angle light |
| February | ★★☆☆☆ | 5°C / -8°C | 90mm (snow) | 15 | 3h | 10.6h | Snow · Cabin weekends · Low-angle light |
| March | ★★☆☆☆ | 9°C / -4°C | 78mm (rain/snow) | 13 | 4h | 11.8h | Cabin weekends · Quiet and local |
| April | ★★★☆☆ | 15°C / 1°C | 66mm | 11 | 6h | 13h | Hiking · Cycling · Spring greenery |
| May | ★★★★★ | 20°C / 5°C | 42mm | 7 | 9h | 14.1h | Hiking · Cycling · Reliable sunshine |
| June | ★★★★★ | 24°C / 9°C | 30mm | 5 | 10h | 14.6h | Hiking · Cycling · Reliable sunshine |
| July | ★★★★★ | 25°C / 10°C | 18mm | 3 | 11h | 14.3h | Reliable sunshine |
| August | ★★★★★ | 24°C / 9°C | 18mm | 3 | 11h | 13.4h | Hiking · Cycling · Reliable sunshine |
| September | ★★★★★ | 20°C / 5°C | 18mm | 3 | 11h | 12.2h | Hiking · Cycling · Reliable sunshine |
| October | ★★★★☆ | 15°C / 1°C | 42mm | 7 | 8h | 11h | Hiking · Cycling · Autumn colour |
| November | ★★☆☆☆ | 9°C / -4°C | 66mm (rain/snow) | 11 | 5h | 9.9h | Cabin weekends · Autumn colour · Low-angle light |
| December | ★★☆☆☆ | 5°C / -8°C | 90mm (snow) | 15 | 3h | 9.4h | Snow · Cabin weekends · Festive season |
| You are planning | Pick | Why |
|---|---|---|
| Sun & beach days | August | 11h daily sunshine, 24°C highs and only 3 rain days. |
| City walking & sightseeing | August | 24°C highs with 13.4h of daylight — long days without heat fatigue. |
| Photography & light | July | 11h of sun and 14.3h daylight give the widest window for golden-hour work. |
| Value & fewer crowds | September | Scores 87/100 — close to peak conditions but outside the busiest window. |
| Cooler-weather travel | October | 15°C highs and 1°C nights suit anyone who dislikes heat. |
Each month in Mammoth is described from long-run climate normals and then rated relative to the other eleven months in the same city. A five-star January in a cold destination means January is one of the best times to be there — not that it beats a Mediterranean summer.
| Factor | Weight | What it measures |
|---|---|---|
| Temperature | Described | Average daytime high and overnight low for the month, shown as measured rather than judged. |
| Precipitation | Described | Monthly millimetres and wet-day count, labelled as snow or rain/snow where temperatures make that the likely phase. |
| Sunshine & daylight | Described | Average daily sunshine hours and astronomical daylight length at mid-month, from the city’s latitude. |
| “Best for” tags | Derived | Applied only when the conditions genuinely support the activity — snow depth-friendly cold for skiing, 13–24°C and low rain risk for hiking, dark evenings at high latitude for aurora. A month with few strong use cases gets fewer tags rather than padded ones. |
| Star rating | Relative | Ranks the month against the other eleven months in the same city. Never a comparison between cities. |
Figures are long-run climate averages, not a forecast for a specific year. This city has no published month-by-month normals on file, so monthly temperatures are interpolated from its summer and winter averages and rainfall is modelled from rain-day frequency.
July is the best all-round month in Mammoth: 25°C highs, 18mm of precipitation and 14.3 hours of daylight, which suits reliable sunshine. The strongest three-month window is June to August.
December — 5°C highs, 90mm of precipitation over roughly 15 days and 9.4 hours of daylight. It is the cheapest and least crowded time to go, and it still works for snow, cabin weekends and festive season.
July is the driest month at 18mm over about 3 rain days, against 90mm in December. Across the year Mammoth records around 621mm.
Yes, but the months are genuinely different trips. July suits reliable sunshine, while December suits snow, cabin weekends and festive season. Pick the month that matches what you want to do.
Daylight ranges from 9.4 hours in December to 14.6 hours in June, calculated from the city's latitude.