Unlock deeper multi-jurisdiction research
Full sub-pages, saves, and alerts are available on paid plans.
Weather & Climate
Seneca, Illinois, United States
Overview
Climate data and monthly weather averages for Seneca.
Key Metrics
Annual Avg
9.9°C
Summer Avg
22.5°C
Winter Avg
-3.7°C
Record High
41.5°C
Record Low
-38.6°C
Annual Precipitation
962.9 mm
Avg Humidity
78%
Summer Humidity
75%
Winter Humidity
85%
Monthly Averages
| Month | High (°C) | Avg (°C) | Low (°C) | Rain (mm) | Humidity (%) | Sunshine (h) | Wind (kph) |
|---|---|---|---|---|---|---|---|
| Jan | 16.6° | -5.2° | -38.6° | 44.9 | 85% | 53 | 58.5 |
| Feb | 19° | -3.5° | -28.5° | 49.3 | 83% | 72 | 64.9 |
| Mar | 26.9° | 3.1° | -24.1° | 63.2 | 78% | 111 | 65.6 |
| Apr | 29.1° | 9.8° | -7.1° | 95.7 | 75% | 142 | 61.5 |
| May | 33.5° | 15.9° | -2.6° | 116.3 | 76% | 169 | 61.5 |
| Jun | 39.1° | 21.3° | 2.9° | 114 | 76% | 184 | 50.5 |
| Jul | 41.5° | 23.5° | 8.4° | 98.9 | 75% | 193 | 40.1 |
| Aug | 39.3° | 22.6° | 7° | 99.8 | 74% | 168 | 36.5 |
| Sep | 35.5° | 18.6° | 1.8° | 83.7 | 73% | 135 | 46.3 |
| Oct | 30.9° | 11.1° | -9.7° | 84.3 | 75% | 92 | 53.8 |
| Nov | 24.1° | 4.1° | -13.8° | 57.3 | 79% | 59 | 60.6 |
| Dec | 20.6° | -2.3° | -24.6° | 55.5 | 86% | 45 | 65.1 |
Frequently Asked Questions
Sources: NASA POWER · Last updated: 2025
Subscribe to unlock the full sub-page depth for additional jurisdictions.
You can keep discovering Oyster publicly, but full multi-jurisdiction depth, tracking, alerts, and exports are part of paid access.