Map from Google - Fatima

The climate of Fátima, Portuguese town located north-east of Lisbon, at 300 metres (1,000 feet) above sea level, is Mediterranean, with mild and fairly rainy winters, and hot, dry summers.
The climate data are taken from the nearby town of Abrantes, whose temperatures are similar, but being located in the plain and a bit more distant from the sea, in summer it's a bit warmer than Fatima, at least during the day.
Here are the average temperatures.
Average temperatures - Abrantes
AbrantesJanFebMarAprMayJunJulAugSepOctNovDec
AbrantesJFMAMJJASOND
Min (°C)558910131515141285
Max (°C)141618202227303128231815
Min (°F)414146485055595957544641
Max (°F)576164687281868882736459

Precipitation amounts to about 600 mm (23.5 in) per year. The rainiest period is from October to March; in the summer it almost never rains. Here is the average precipitation.
Average precipitation - Abrantes
AbrantesJanFebMarAprMayJunJulAugSepOctNovDecYear
AbrantesJFMAMJJASONDY
Prec. (mm)8060905040200030608090600
Prec. (in)3.12.43.521.60.8001.22.43.13.523.6
Days87765300467962

Winter, from December to February, is mild, but also quite rainy. Very cold days are rare, even though sometimes at night the temperature can drop to freezing (0 °C or 32 °F) or a little below.

Spring, from March to May, is mild; it's initially unstable and rainy in March, and gradually becomes more stable and sunny.

Summer, from June to August or mid-September, is hot and sunny; given the proximity of the ocean, it is less hot than inland locations of Spain. Sometimes, however, it can be definitely hot, with highs about 35 °C (95 °F).

Autumn, from mid-September to November, is initially warm and sunny, but over the weeks it gradually becomes milder and wetter.

The amount of sunshine in Fátima is great in summer, when blue skies prevail, it's good in spring, and it's only decent in autumn and winter, when cloud banks linked to disturbances from the Atlantic Ocean pass more frequently.

Fatima

When to go

The best time to go to Fátima is spring, in April and May. Summer is a good period, but sometimes it can be definitely hot. September is a good month, although sometimes it can be hot, at least in the first half. In October, the temperatures are pleasant, but the rains begin to become more frequent.