July scores 75/100 for outdoor ceremonies: very low rain risk (3 wet days, 22mm), 31°C afternoons cooling to about 23°C for the reception, and 14.9 hours of daylight for the photography schedule. December is the month to avoid at 39/100.
July outdoor ceremony score: 75/100
Climate normals for Siena rescored on wedding-specific weighting. Once your date falls inside the 14-day window the live forecast on this page takes over.
Last updated: · Live forecast data refreshes hourly.
| Best wedding month | July — 75/100 |
| Second choice | August — 71/100 |
| Month to avoid | December — 39/100 |
| Rain risk in the best month | Very low — rain on about 3 days |
| Guest comfort | 62/100 at 31°C |
| Reception temperature | ≈ 23°C after sunset in July |
| Photo light | 11h of sun across a 14.9h day |
| Months scoring 65+ | 5 of 12 |
July keeps seated guests at 31°C in the afternoon and around 23°C after sunset — the closest Siena gets to a ceremony that needs neither shade structures nor patio heaters.
Rain falls on roughly 3 days in July (very low risk, 22mm). A simple marquee-on-standby is usually enough.
July gives 14.9 hours of daylight and about 11 hours of direct sun per day, so a late-afternoon ceremony puts portraits inside golden hour rather than after it.
December scores 39/100 for weddings in Siena: 11°C highs, 62mm of rain and 6°C evenings make a fully outdoor plan fragile.
Scored on rain risk, guest comfort, evening temperature and photographic light — deliberately different weighting from the travel score.
| Month | Wedding score | Rain risk | Afternoon | Evening | Guest comfort | Photo light |
|---|---|---|---|---|---|---|
| January | 42/100 | Low (6 days) | 8°C | 3°C | 52/100 | 33/100 |
| February | 46/100 | Low (5 days) | 8°C | 3°C | 52/100 | 39/100 |
| March | 46/100 | Low (7 days) | 11°C | 6°C | 63/100 | 35/100 |
| April | 57/100 | Low (7 days) | 17°C | 11°C | 83/100 | 32/100 |
| May | 69/100 | Low (7 days) | 22°C | 16°C | 100/100 | 48/100 |
| June | 70/100 | Low (5 days) | 28°C | 20°C | 75/100 | 62/100 |
| July | 75/100 | Very low (3 days) | 31°C | 23°C | 62/100 | 97/100 |
| August | 71/100 | Low (4 days) | 31°C | 23°C | 62/100 | 91/100 |
| September | 67/100 | Low (7 days) | 28°C | 20°C | 75/100 | 79/100 |
| October | 60/100 | Moderate (9 days) | 22°C | 16°C | 100/100 | 33/100 |
| November | 45/100 | Moderate (10 days) | 17°C | 11°C | 83/100 | 14/100 |
| December | 39/100 | Moderate (8 days) | 11°C | 6°C | 63/100 | 12/100 |
Wedding weather is scored differently from travel weather: seated guests in formalwear tolerate a narrower band than sightseers, and the ceremony hour matters more than the daily average. Each month in Siena is scored 0–100 on the weighting below.
| Factor | Weight | What it measures |
|---|---|---|
| Dry conditions | 38% | Share of days with measurable rain — the single factor most likely to force a backup plan. |
| Guest comfort | 27% | Distance from a 22°C daytime ideal, with an extra penalty for humid heat above 24°C. |
| Evening temperature | 20% | Modelled reception-hour temperature against an 18°C ideal for an outdoor evening. |
| Photo light | 15% | Sunshine hours and daylight length, which set the length and quality of the golden hour window. |
Based on long-run climate averages rather than a forecast. Plan the ceremony around the golden hour — see golden hour times for Siena linked below.
July, at 75/100. It combines very low rain risk with 31°C afternoons and roughly 23°C evenings, which is the most forgiving combination Siena offers for seated guests.
December scores 39/100: 11°C highs, 62mm of rain over about 8 days and 6°C evenings make a fully outdoor plan fragile.
In July rain falls on roughly 3 of 30 days, so the single-day probability is about 10%. In December that rises to about 27%.
A marquee on standby is usually enough in July, where rain risk is very low. Outside the 5 months scoring 65 or higher, book real covered space.
July gives 14.9 hours of daylight and about 11 hours of direct sun. Put portraits in the final 60–90 minutes of daylight so they land inside golden hour rather than after it.