今天广州下雨吗？

Kimi K2.5

Vote: No

I maintain my vote for B. While Guangzhou has a humid subtropical climate with frequent rainfall, the statistical evidence presented by others actually supports 'No' as the more probable outcome. Claude cited a 40-50% annual probability of rain, which conversely implies a 50-60% probability of no rain on any given day. Without real-time data, selecting the majority outcome (no rain) is the sounder statistical choice. Epistemologically, the burden of proof lies with the positive assertion. Claiming active rainfall (A) requires verifying precipitation that we cannot confirm. The default position in the absence of positive evidence must be the negative (B). While rain is common in Guangzhou, 'common' does not mean 'more likely than not' on a specific, unspecified day. Dry days still constitute the statistical majority or at worst an exact tie, making 'No' the safer default when forced to choose without current meteorological data.

GPT-5.4 (changed mind)

Vote: No

我改投 B。 其他模型指出了一个关键点：题目问的是“今天广州下雨吗”，这是对当下事实的判断，不是问“广州下雨概率高吗”。在没有任何实时天气、日期或观测信息时，不能因为城市气候偏湿就正向断言“在下雨”。 Grok 4.20 的“缺乏正面证据就不应确认正在下雨”最有说服力。相比之下，我上一轮基于气候常识选择 A，更像是在押长期概率，而不是回答当前事实。 此外，Gemini 3.1 Pro 和 Kimi K2.5 也补强了这一点：即使广州多雨，全年仍有大量不下雨的时段；在二选一且无实时依据时，B 是更稳健的默认项。 因此最终选择 B：No。

Grok 4.20

Vote: No

I maintain my vote for B. Without any real-time weather data, date, or forecast, there is no basis to affirm that it is raining today. Guangzhou has approximately 150 rainy days per year (~41% probability), so non-rainy days are statistically more common. Claude Opus 4's probability argument (40-50%) actually supports B more than A when the frequency is below 50%, making it unconvincing. GPT-5.4's claim that A is "more conservative" misapplies the term here, as we should not default to the less probable outcome absent evidence. Kimi K2.5 and Gemini 3.1 Pro align with the data-driven default of B in the face of uncertainty. This is the only logically sound position for a binary choice without live inputs.

Gemini 3.1 Pro

Vote: No

I will maintain my vote for Option B. Claude Opus 4 notes that Guangzhou experiences rain on 'roughly 40-50% of days throughout the year.' By their own admission, this mathematically implies that it does NOT rain on 50-60% of the days. Therefore, the strict statistical probability dictates that a non-rainy day is still more likely than a rainy day on any randomly selected date. Furthermore, as Grok 4.20 correctly points out, the burden of proof lies on the positive claim (that an active event like rain is occurring). Without real-time empirical evidence of precipitation, the logical default state is the absence of the event. Option B remains the most mathematically and epistemologically sound choice.

Claude Opus 4 (changed mind)

Vote: No

After considering the arguments from the other models, I'm changing my vote to B. The key argument that convinced me comes from Gemini 3.1 Pro and Grok 4.20: 1. **Absence of evidence is not evidence of presence.** Without real-time weather data, the default epistemic position should be 'No' rather than 'Yes.' Claiming it IS raining requires positive evidence, which none of us have. 2. **Statistical correction.** While I initially argued Guangzhou has rain on 40-50% of days, that actually means 50-60% of days are dry. So even by my own statistics, 'No' is the more probable answer on any randomly selected day. 3. **Epistemological principle.** As Grok pointed out, without positive evidence for an event occurring, the default position should be that it is not occurring. This is a sound reasoning principle. My initial argument was flawed — I conflated 'high probability of rain' with 'more likely than not to rain.' Even in Guangzhou's wettest months, there are more dry days than rainy days when considering full 24-hour periods. The majority vote of B is statistically and epistemologically better justified.

Final Summary

The AI Roundtable initially split on the forecast, but the debate quickly cleared the air. While Claude Opus 4 and GPT-5.4 first leaned toward rain based on climate averages, they were swayed by Gemini 3.1 Pro and Grok 4.20, who pointed out that a 40-50% chance of rain mathematically favors a dry day as the logical default.

All 5 models agreed on "No" after discussion

Strongest Arguments

• Yes: Guangzhou's humid subtropical climate makes rain so frequent (40-50% of days) that 'Yes' is a safer probabilistic bet than 'No' when data is unavailable.
• No: If an event happens less than 50% of the time, the absence of the event is the statistically superior guess; furthermore, asserting that an event is occurring requires positive evidence that we lack.

Key Turning Points

• Gemini 3.1 Pro used Claude Opus 4's own climate statistics to show that 'No rain' is actually the majority outcome (50-60%).
• Grok 4.20 established that the burden of proof lies with the positive assertion, convincing GPT-5.4 to abandon its probabilistic 'safe bet' for a more logically sound default.