Viçosa, Brazil (Minas Gerais state) has a humid subtropical climate (Cwa) characterized by a hot, rainy summer and a cooler, dry winter【14†L15-L23】. February and early March fall in late summer/early autumn, during the peak of the rainy season. Typical climate conditions for this period include warm temperatures, very high humidity, frequent rainfall, and generally low vapor pressure deficit (VPD). Below is a breakdown of expected climate metrics for Feb–early Mar and how they compare to the sensor data, highlighting any anomalies.
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Warm Daytime Highs: Late February is usually the hottest time of year in Viçosa【8†L35-L43】. Afternoon temperatures typically reach the upper 20s °C, often around 27–30 °C on average【8†L31-L39】【19†L1-L4】. For example, climate normals show average highs of ≈27.1 °C in February and ≈25.9 °C in March【8†L31-L39】【7†L9-L17】. It’s not uncommon for some days to get even warmer – highs around 30°C or a bit above can occur in this season【18†L1-L4】.
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Mild Nights: Overnight lows cool to the upper teens °C. Typical nights see temperatures about 17–20 °C【8†L41-L49】【19†L1-L4】. For instance, average lows are ~18°C in both Feb and Mar【8†L41-L49】【7†L37-L45】. Early mornings can feel relatively cool compared to the hot afternoons, but remain far from cold (frost is essentially unheard of in this season).
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Comparison to Sensor Data: The provided sensor data (Feb–early Mar 2025) generally aligns with these ranges, but one notable anomaly was a spike in temperature around mid-February. On Feb 18, 2025, the station recorded an afternoon high of about 33.3 °C, which is well above the typical February average high【8†L31-L39】. This reading approaches the upper extreme for Viçosa’s climate (historically, temperatures rarely exceed ~36 °C in this region【14†L15-L23】【14†L17-L24】). Such a hot day in late February is unusually high relative to climatology, indicating a brief hot spell. By contrast, most days in the sensor period had highs in the mid-20s (especially when rain or cloud cover was present), which is normal. On the other end, the lowest nighttime temps recorded (around 15–16 °C on a few nights) were slightly cooler than the average low ~18 °C, but still within a reasonable range for summer nights (not an extreme anomaly).
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High Humidity: February and March are extremely humid months in Viçosa. Average relative humidity is about 87% in February and rises to around 90% in March, making March the most humid month of the year【8†L59-L67】【7†L23-L27】. It’s common to have mornings with near-saturated air (fog or dew is frequent), and even afternoons remain muggy unless a temporary dry spell occurs. This persistently high humidity is a hallmark of the rainy season in this region.
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Vapor Pressure Deficit (VPD): VPD is a measure of the drying power of air (the difference between how much moisture the air could hold and how much it does hold at a given temperature). In a climate as moist as Viçosa’s summer, VPD typically stays low because the air is near saturation. For context: a high VPD (>1.0 kPa) indicates dry air that can absorb a lot more moisture, whereas a low VPD means the air is near saturation【11†L33-L41】. A VPD of 0 kPa would mean 100% humidity (saturated air)【11†L37-L41】. Given average conditions (~25–30 °C with 87–90% RH), one would expect VPD values generally well below 1 kPa for much of the day, especially in mornings/evenings when RH approaches 100%. During the warmest part of the day, VPD might increase but usually remains moderate due to the high overall humidity (e.g. on a 26 °C day with 90% RH, VPD would be on the order of only ~0.3–0.5 kPa, which is very low).
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Comparison to Sensor Data: The sensor data confirms the very humid conditions – frequently the VPD dropped to near 0 kPa at night, indicating 100% RH (saturated air, likely dew formation or fog, which is normal for nights in the wet season). Daytime VPD values on typical rainy or cloudy days stayed low (often <1.5 kPa). However, an anomalous VPD spike accompanied the heat on Feb 18. When the temperature hit ~33°C that day, VPD climbed to ~3.3 kPa (as recorded by the station). This is unusually high given the season, and implies the air was much drier than normal (a VPD ~3+ kPa at ~33°C corresponds to a relative humidity around only 35–40%). Such dry air is not typical for February in Viçosa’s climate. It suggests a brief drop in humidity – perhaps a short dry spell or “veranico” (a mini dry-hot spell often observed in Brazilian summers) occurred. In normal wet-season conditions, VPD rarely exceeds ~1–2 kPa even in the afternoon, so the ~3.3 kPa reading stands out as a significant anomaly【8†L59-L67】【11†L33-L41】. Once rains returned, the sensor showed humidity rising again (VPD falling back near zero at times), consistent with typical moist conditions.
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Heavy Rainfall: February and March are part of Viçosa’s rainy season, so frequent, heavy precipitation is expected. Climatological data show large monthly totals – on the order of 150–180 mm of rain per month in this period【8†L67-L75】【7†L65-L73】. (For example, one source reports about 155 mm in Feb and 183 mm in Mar on average【8†L67-L75】, while another source gives ~135–140 mm for these months【5†L35-L43】【17†L36-L44】 – all indicating very wet conditions.) In practical terms, this means rain falls nearly every day. February typically has ~18–25 rainy days and March about 25–28 rainy days (nearly the entire month) according to climate records【5†L35-L43】【8†L71-L77】. It’s often overcast or cloudy; there are only about 1–2 “sunshine days” (clear days) in the whole month during this season【8†L91-L95】.
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Rainfall Patterns: The rainfall in late summer is usually convective – afternoon showers or thunderstorms are common. These can bring intense downpours, contributing a large fraction of the monthly rain in short bursts. It’s also common to have intermittent light rain or drizzle on many days. Overall, soil and air remain very moist, and flooding or waterlogging can happen in extreme events. March, being the tail end of summer, can still be extremely wet. (Notably, by April the rainy season retreats – average rainfall drops sharply to ~64 mm in April【7†L67-L75】 – but Feb–Mar remain in the peak wet period.)
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Comparison to Sensor Data: The sensor data from Feb to early Mar 2025 captured the expected pattern of heavy rain followed by high humidity, but it also shows a few anomalies in rainfall distribution. In line with climate norms, we do see significant rain events in late February: for example, the station recorded heavy rainfall on Feb 23–24, with an estimated ~25 mm and ~23 mm of rain those days respectively (rates peaking around 35–38 mm/hour during downpours). This is typical for the season. However, a noteworthy anomaly is the prolonged dry spell from around Feb 26 through early March. According to the sensor, virtually no measurable rain fell between Feb 26 and Mar 2, and only a trivial drizzle on Mar 3 (a few tenths of a millimeter). Such a multi-day rainless period is unusual for late February/early March, given that climatology suggests rain on most if not all of those days【8†L71-L77】. In other words, the start of March 2025 was much drier than normal. By early March, one would typically expect a continuation of frequent rains (March’s long-term average is ~183 mm over ~28 rainy days【7†L65-L73】【8†L73-L77】), yet the station recorded almost no rain in that first week of March – a clear deviation from the norm. This anomaly in the rainfall pattern likely contributed to the earlier mentioned higher temperatures and VPD (since lack of rain and clouds allowed more heating and drying of the air during that stretch). It’s possible that this dry spell reflects a short-term climatic fluctuation (for instance, a break in the usual rain-bearing systems). After Mar 3–4, one would normally expect rains to resume given March’s wet reputation, though the provided data ends on Mar 4. Lastly, the sensor’s measured total rainfall for the latter half of February (from Feb 18 onward) was on the order of ~50 mm, which is somewhat lower than half the monthly normal【8†L67-L75】 – this could indicate either the early February portion (not in data) had more rain or that Feb 2025 was slightly drier than average overall. In summary, the notable anomalies in the sensor data relative to typical climate were the brief hot/dry episode (unusually high temperature and VPD) and the lack of rain over several consecutive days, both of which diverge from the expected constantly warm-and-wet conditions of a Viçosa late summer.
To put it all together, late February to early March in Viçosa is normally hot, extremely humid, and rainy. Daytime temperatures in the high-20s°C with sultry humidity (~90% RH) are the norm【8†L59-L67】【19†L1-L4】. Frequent rainfall keeps temperatures from spiking too high on most days and maintains near-saturated air (low VPD). Overcast skies dominate, with very little completely clear weather【8†L91-L95】. This period represents the height of the wet season, before a transition to drier conditions by mid-autumn. Any significant departure from this pattern – such as an unusually hot, dry afternoon or several rain-free days in a row – is an anomaly worth noting. By comparing the sensor data to climate records, we identified those anomalies (e.g. the Feb 18 heat/VPD spike and the late Feb–early Mar dry spell) as likely outliers against the backdrop of Viçosa’s typical Feb–Mar climate【8†L31-L39】【8†L71-L77】.
Sources: Historical climate data for Viçosa (Minas Gerais) including average temperatures, humidity, and rainfall【8†L59-L67】【8†L67-L75】【7†L25-L33】【7†L61-L69】; weather summaries for Feb and Mar in Viçosa【5†L30-L37】【17†L28-L36】; and agronomic literature on vapor-pressure deficit interpretation【11†L33-L41】. These records provide the baseline for typical conditions, against which the 2025 sensor readings were compared to spot unusual deviations. All climate statistics are based on long-term observations, while the sensor data reflect actual conditions in Feb–Mar 2025.