Spring (mid-March through late May) or September-October. Spring offers the most comfortable weather (afternoon highs around 75F), wildflower season, the valley's liveliest winery event calendar, and smaller crowds than summer. September-October is equally compelling for harvest season grape stomps, Temecula Valley Wine Month (September), warm highs near 83F, and lower accommodation costs than peak summer. Both windows avoid the intense 90F+ heat of July-August
| Month | High (°F) | Low (°F) | Notes |
|---|---|---|---|
| Jan | 66 | 43 | mild & mostly dry |
| Feb | 67 | 44 | mild & mostly dry |
| Mar | 70 | 47 | mild & mostly dry |
| Apr | 74 | 50 | warm & sunny |
| May | 77 | 54 | warm & sunny |
| Jun | 85 | 59 | warm & sunny |
| Jul | 90 | 65 | hot & sunny |
| Aug | 92 | 66 | hot & sunny |
| Sep | 89 | 64 | hot & sunny |
| Oct | 82 | 56 | warm & sunny |
| Nov | 74 | 49 | warm & sunny |
| Dec | 65 | 43 | mild & mostly dry |