Here's the updated code:
```python
plt.style.use("ggplot")
fig, ax = plt.subplots()
ax.plot(seattle_weather["MONTH"], seattle_weather["MLY-TAVG-NORMAL"])
plt.show()
```
We use `plt.style.use("ggplot")` to set the plot style to "ggplot". We then create a new figure and axis using `fig, ax = plt.subplots()`. Finally,