Modesto, CA Climate & Monthly Averages
Modesto has a semi-arid climate. July is the hottest month, averaging 100° by day; December is the coldest at 56°.
Sunshine is a defining feature of Modesto's climate
Modesto runs on a dry-summer rhythm: the warmest months are also the driest. July averages less than 1 mm while the wet season peaks in January at 4.0 inches (103 mm). Highs range from 56°F (14°C) to 100°F (38°C).
How sun, temperature and rain fit together
December bottoms out at 56°F (14°C) in daylight, 40°F (5°C) after dark. July is the warm end of the year, averaging 100°F (38°C) by day and 66°F (19°C) overnight. The gridded 2015-2024 daily record for this location tops out at 119°F (48°C) and bottoms at 28°F (-2°C) - decade extremes, not all-time station records. Average highs hold at or above 30°C for 4 months of the year, June through September being the unbroken run.
Three of the twelve months pair mild highs with fewer than twelve wet days; the longest unbroken run is March through April. January is the wettest month at 4.0 inches (103 mm) over 10 days; July is the driest. Days and nights are about 14°C apart on average - wider than almost anywhere else we cover. Sunshine averages 10.6 hours a day over the year - sunnier than roughly 85% of the cities we track, peaking in July at 13.9 hours.
More climate facts for Modesto
- Hottest month: July - highs near 100°F (38°C)
- Coldest month: December - highs near 56°F (14°C)
- Decade extremes (2015-2024): 119°F (48°C) high · 28°F (-2°C) low
- Wettest month: January (10 rainy days) · Sunniest: July (13.9 h sun/day)
- Climate type: semi-arid
- Annual swing: 19°C between the average warmest and coolest month · day to night: 14°C
- Months averaging 30°C or hotter: 4
- Average humidity: 57%
The most comfortable sunny-weather window
Best time to visit Modesto
The best time to visit Modesto is generally April to May and October to November, when temperatures sit either side of the peak heat rather than in it. Daytime temperatures in that window sit near 73°F (23°C), with rain on about 4 days a month. For the same question asked the other way round, see where else is warm in April.
What to pack
Pack for Modesto with lightweight, breathable clothing and serious sun protection and a warm jacket and layers for the cooler season. July nights average 66°F (19°C), so evenings rarely match the afternoons.
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 57° | 41° | 10 | 4.0 in | 6.6 h/day | 9.8 h | 31% | 83% |
| February | 62° | 42° | 7 | 2.5 in | 8.9 h/day | 10.7 h | 25% | 72% |
| March | 66° | 45° | 9 | 3.1 in | 9.6 h/day | 11.8 h | 29% | 69% |
| April | 74° | 50° | 4 | 1.1 in | 11.4 h/day | 13.1 h | 14% | 57% |
| May | 83° | 55° | 3 | 0.7 in | 13.2 h/day | 14.2 h | 9% | 48% |
| June | 94° | 62° | 0 | 0.0 in | 13.7 h/day | 14.7 h | 0% | 38% |
| July | 100° | 66° | 0 | 0.0 in | 13.9 h/day | 14.5 h | 0% | 36% |
| August | 97° | 65° | 0 | 0.0 in | 13.0 h/day | 13.6 h | 1% | 41% |
| September | 91° | 62° | 1 | 0.1 in | 11.7 h/day | 12.4 h | 2% | 44% |
| October | 81° | 55° | 2 | 0.9 in | 10.2 h/day | 11.1 h | 7% | 50% |
| November | 65° | 44° | 6 | 1.7 in | 8.3 h/day | 10.1 h | 19% | 69% |
| December | 56° | 40° | 9 | 3.9 in | 6.6 h/day | 9.6 h | 29% | 80% |
Modesto month by month
Each card shows the average high and low. The bar places that month between Modesto's coldest night and warmest afternoon.
January
- Rain
- 10 days
- Sunshine
- 6.6 h
- Daylight
- 9.8 h
February
- Rain
- 7 days
- Sunshine
- 8.9 h
- Daylight
- 10.7 h
March
- Rain
- 9 days
- Sunshine
- 9.6 h
- Daylight
- 11.8 h
April
- Rain
- 4 days
- Sunshine
- 11.4 h
- Daylight
- 13.1 h
May
- Rain
- 3 days
- Sunshine
- 13.2 h
- Daylight
- 14.2 h
June
- Rain
- 0 days
- Sunshine
- 13.7 h
- Daylight
- 14.7 h
July
- Rain
- 0 days
- Sunshine
- 13.9 h
- Daylight
- 14.5 h
August
- Rain
- 0 days
- Sunshine
- 13.0 h
- Daylight
- 13.6 h
September
- Rain
- 1 day
- Sunshine
- 11.7 h
- Daylight
- 12.4 h
October
- Rain
- 2 days
- Sunshine
- 10.2 h
- Daylight
- 11.1 h
November
- Rain
- 6 days
- Sunshine
- 8.3 h
- Daylight
- 10.1 h
December
- Rain
- 9 days
- Sunshine
- 6.6 h
- Daylight
- 9.6 h
Looking for warmer alternatives? Browse warm places by month, or compare Modesto's coolest part of the year: December, January, February.
Seasonal weather under Modesto's sunnier skies
Spring (March through May)
Spring in Modesto brings comfortable warmth, with daytime highs averaging 74°F (24°C) and nights around 50°F (10°C); rain comes on about 16 days over the three months. Daylight is generous - around 11.4 hours of sun a day.
Summer (June through August)
Summer turns very hot here - highs near 97°F (36°C), nights near 65°F (18°C), and precipitation is essentially absent. Daylight is generous - around 13.5 hours of sun a day.
Fall (September through November)
Through fall, Modesto settles into easy warmth: 79°F (26°C) by day, 54°F (12°C) after dark, and rain comes on about 8 days over the three months. Daylight is generous - around 10.1 hours of sun a day.
Winter (December through February)
Winter in Modesto stays on the cool side of mild, with daytime highs averaging 59°F (15°C) and nights around 41°F (5°C); expect showers on roughly 26 days across the season.
How unusual is Modesto?
- Rain or snow reaches the ground on 51 days a year - fewer wet days than all but 9% of the 3496 cities we track.
- 58% of the year's precipitation falls in its wettest three months - more seasonal than 89% of the 3496 cities we track.
- Relative humidity averages 57% - drier than all but 11% of the 3496 cities we track.
These comparisons use the same ten-year window for every city in the dataset.
Modesto temperature extremes in the 2015–2024 dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.