Last updated: June 24, 2025
In September, the average temperature in Northumberland, United States is a pleasant 19°C (67°F). You can expect temperatures to range from a cool 2°C (36°F) to a warm 33°C (92°F). This month also sees an average precipitation of 115 mm (4.5 in) spread over 9 days, contributing to an average humidity level of 66%. Enjoy the varying weather!
In September in Northumberland, the average temperature is 19°C (67°F), with maximums reaching 33°C (92°F) and minimums dropping as low as 2°C (36°F). This range makes it a great time to visit for those who enjoy mild weather but should be prepared for both warm days and cooler nights.
In Northumberland in September, the precipitation amount is 115 mm (4.5 in) over the course of 9 days, indicating a relatively wet period for the region.
In Northumberland in September humidity is 66%. With an average temperature of 19°C (67°F), this humidity feels like a warm blanket wrapping around you, making it mildly uncomfortable for traveling, as you may find yourself needing to frequently stop for hydration and to seek shade from the sun.
In Northumberland in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Northumberland.
UV Risk Categories
Weather in Northumberland varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Northumberland, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -1°C (31°F) | 71 mm (2.8 inches) | 87% | moderate |
| February Weather | 1°C (33°F) | 98 mm (3.9 inches) | 85% | moderate |
| March Weather | 4°C (40°F) | 89 mm (3.5 inches) | 85% | high |
| April Weather | 10°C (51°F) | 106 mm (4.2 inches) | 83% | very high |
| May Weather | 16°C (62°F) | 124 mm (4.9 inches) | 75% | very high |
| June Weather | 21°C (70°F) | 89 mm (3.5 inches) | 73% | very high |
| July Weather | 24°C (76°F) | 128 mm (5.0 inches) | 65% | very high |
| August Weather | 23°C (74°F) | 118 mm (4.6 inches) | 62% | very high |
| September Weather | 19°C (67°F) | 115 mm (4.5 inches) | 66% | very high |
| October Weather | 14°C (57°F) | 120 mm (4.7 inches) | 79% | high |
| November Weather | 5°C (42°F) | 94 mm (3.7 inches) | 87% | moderate |
| December Weather | 2°C (35°F) | 88 mm (3.5 inches) | 85% | low |