| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 19.7° | 5.7° | 18.8mm | 3.1 | 93 |
| February | 21.6° | 7° | 27.8mm | 3.4 | 93 |
| March | 25.9° | 10° | 21.9mm | 2.8 | 94 |
| April | 30.4° | 13.5° | 7mm | 1.4 | 84 |
| May | 35.2° | 18.4° | 2.2mm | 0.7 | 66 |
| June | 40.4° | 23.4° | 1mm | 0.3 | 46 |
| July | 41.9° | 27.6° | 22.3mm | 2.9 | 35 |
| August | 41° | 27.2° | 25.3mm | 3.3 | 37 |
| September | 38.2° | 23.5° | 17.5mm | 2.2 | 51 |
| October | 31.7° | 16.1° | 14.5mm | 2 | 77 |
| November | 24.6° | 9.5° | 11.4mm | 1.6 | 97 |
| December | 19° | 5.3° | 17.8mm | 3.3 | 90 |
January in Surprise averages a daily high of 19.7°C with nights around 5.7°C. Expect roughly 3.1 wet days totalling 18.8mm. Comfortable conditions for being outdoors all day.
February in Surprise averages a daily high of 21.6°C with nights around 7°C. Expect roughly 3.4 wet days totalling 27.8mm. Comfortable conditions for being outdoors all day.
March in Surprise averages a daily high of 25.9°C with nights around 10°C. Rain is rare — about 2.8 wet days and 21.9mm across the month. Comfortable conditions for being outdoors all day.
April in Surprise averages a daily high of 30.4°C with nights around 13.5°C. Rain is rare — about 1.4 wet days and 7mm across the month. Comfortable conditions for being outdoors all day.
May in Surprise averages a daily high of 35.2°C with nights around 18.4°C. Rain is rare — about 0.7 wet days and 2.2mm across the month. Generally workable, with some weather to plan around.
June in Surprise averages a daily high of 40.4°C with nights around 23.4°C. Rain is rare — about 0.3 wet days and 1mm across the month. Demanding conditions — pack for it and plan indoor options.
July in Surprise averages a daily high of 41.9°C with nights around 27.6°C. Rain is rare — about 2.9 wet days and 22.3mm across the month. Demanding conditions — pack for it and plan indoor options.
August in Surprise averages a daily high of 41°C with nights around 27.2°C. Expect roughly 3.3 wet days totalling 25.3mm. Demanding conditions — pack for it and plan indoor options.
September in Surprise averages a daily high of 38.2°C with nights around 23.5°C. Rain is rare — about 2.2 wet days and 17.5mm across the month. Demanding conditions — pack for it and plan indoor options.
October in Surprise averages a daily high of 31.7°C with nights around 16.1°C. Rain is rare — about 2 wet days and 14.5mm across the month. Comfortable conditions for being outdoors all day.
November in Surprise averages a daily high of 24.6°C with nights around 9.5°C. Rain is rare — about 1.6 wet days and 11.4mm across the month. Comfortable conditions for being outdoors all day.
December in Surprise averages a daily high of 19°C with nights around 5.3°C. Expect roughly 3.3 wet days totalling 17.8mm. Comfortable conditions for being outdoors all day.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Surprise peaks at 97.
Based on 30 years of records, November–March scores highest for comfort in Surprise, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 41.9°C.
February is the wettest, averaging 27.8mm of rain across roughly 3.4 wet days.
December is the coolest month, with average daily highs around 19°C.