Weather

Print the weather report for the day of your offence from at least two different sources and note the date and time you accessed this information. Environment Canada has an excellent historical weather database.

Why are you doing this? In court you are going to challenge the officer's recollection of the facts. That's why you ask "What was the weather like?" If the officer is smart he'll say he doesn't remember which also casts doubt to his recollection of the facts. If the officer tells you what the weather was like, you can submit your weather report as a rebuttal to his recollection of facts.

Weather also plays a factor in road conditions, visibility, etc. You can be charged for going too fast for conditions. If it is slippery and icy, travelling 5 km/hr below the speed limit may still be too fast for road conditions and you can get a ticket for careless driving. To dispute that, you need a weather report.

An officer using a lidar gun without a tripod is trying to hit a 3cm square dot on your licence plate from a distance of 100 metres or more. That's quite a difficult shot on the best day. If there is any wind, it will affect his aim and call into question his ability to take an accurate reading. The Weather Underground has excellent hourly measurements including wind speed.