Embedded above is a chart showing the current weather conditions relavent to visual astronomy. This data and chart is made by A. Danko for his ClearDarkSky project, which you can find here: https://www.cleardarksky.com/c/PlmIsldMAkey.html along with a detailed explanation of how to read the chart. I'll summarize some important points here but for more information, or if you're still confused, follow the link to his site.
Each square on the chart represents the quality of a certain weather condition for each hour.
The coloring should be relatively logical: a whiter box means higher cloud cover, lower transparency, worse seeing, and lower darkness. For smoke, a redder box means denser/more prevalent smoke; wind is ranked from dark blue (lower wind) to white (high winds); humidity is ranked from red (highest) to dark blue (lowest); and temperature has roughly freezing (0 deg C) mapped to white, getting darker red (hotter) or blue (colder) as the temperature deviates from this point.
While all of the weather tracked above will affect how much fun, or how effectively you may be able to observe, some conditions are irreconcilable with visual astronomy.
Cloud cover, transparency, and darkness are direct indicators of whether or not you'll be able to see night sky objects. At a time where all of these boxes are white, you likely won't be able to see anything, at all.
Seeing is a more experimental metric governing several atmospheric phenomenon that can affect how effectively light gets to your telescope. Note that the weather forecast is calibrated for telescopes larger than the school's Celestron 130GT's, meaning forecasted seeing limitations may not translate effectively. Seeing is not a measure of whether or not you'll be able to see anything in the night sky, as the other metrics may control, however it will have an effect on how much detail you are able to resolve.
Humidity should be treated much the same as seeing, although it is a more concrete measurement. While low humidity will lead to more enjoyable viewing with greater resolution, high humidity will not make seeing impossible. Instead, it mostly will affect telescopes with a front element exposed to free-flowing air such as a camera lens. The nature of Newtonian telescopes is such that they naturally avoid the issues described below, and while it is possible to be limited by it, this is exceedingly rare. Cooling nighttime air coupled with high humidity is a recipe for dew: condensation on lenses (and optical tubes, and anything else that changes temperature at the right rate). This dew will make observing a lot less fun. You can wipe it off whenever you start to notice it, and for visual astronomy with a small scope this should be sufficient, however for astrophotography or larger optics, dew management systems will be necessary.
Smoke fits in somewhere between the two categories described above. It is not necessarily a strict limitation on observing--instead, in mild smoke one may experience the same effects as with mediocre seeing: objects are visible but less detailed. Smoke can, however, also overrule and completely restrict seeing. In high smoke conditions, it should be treated the same as a high-percentage cloud cover.
Wind and temperature strictly affect how much fun you might have observing. Temperature should make sense: whatever temperature in which you can tolerate standing around in the dark is a good temperature to look for. Wind can affect observing, however it more so affects astrophotographers and those with more robust optical tube assemblies than the Celestron 130GT. High wind conditions can induce instability in a telescope that likely won't affect visual observation, however extended over the length of an exposure can significantly reduce effective tracking time. An effect of wind worth keeping in mind is its affect on how quickly you get cold. If you could normally tolerate the night's temperature, however the wind is high, plan on layer up more, as high winds and relatively stationary activity is a recipe to get cold, fast. Trust me, I know.